The Cutting Edge of Forensic Technology

developing areas of investigation. And today we look at forensic science as a collection of these various techniques and technologies to to investigate crime and to solve crime. So today I wanted to look more at some of the actual tech use. I was kind of light on the tech in the last episode. I was talking more about the evolution of the ideas behind it, because that really informs how the tech itself evolved. And today we're gonna look

a little more closely at that now. In the last episode, I did mention the comparison microscope, that is a microscope that is typically a pair of light microscopes. Isn't the microscopes that use light as the medium to magnify stuff into your eyeballs, So the companion or comparison microscope is a pair of these right, it's it's essentially side by side two light microscopes that are actually bridged together, but on casual glance it looks almost like kind of binoculars

in a way. And here's a quick rundown on how light microscopes work so that you can understand what a comparison microscope is able to do. A basic upright light microscope the kind you might see in a high school lab or even you know, I guess elementary school and middle school labs. Now when when I was a student, they didn't let a play with us until we were essentially high schoolers. But you are probably familiar what what

these look like. It's that little upright microscopees gun. I piece at one end has a little platform it's called the stage where you would put a sample to h to examine. Well, they're called light microscopes because they have a light source at the base. Typically, your basic upright light microscope does that shines light up through a sample so that you can see it when you're looking through the I piece above. The light source is a special

lens called a condenser. Now, the condenser's purpose is to redirect a divergent beam of light from a light source into a converging beam to illuminate a sample. So essentially you're focusing light on the smaller area that the sample itself will sit on, and of course that is on the part of the microscope that's called the stage. The microscope has what is called an objective lens that's near the end opposite where you put your eye, so this

is the end that's closest to the sample. Uh. The lens that's close to your eye, by the way, is fittingly called the ocular lens. So the objective lens and the condenser are aligned to focus on the same spot of a sample, so the light from the condenser is hitting the same region of a sample that the objective lens is focused on. The job of the objective lens is to gather light from the point of observation and

focus that light to produce a real image. Objective lenses are in stuff like cameras and telescopes to they're not just in microscopes. The lenses in the eyepiece of the microscope do the majority of the actual magnification. So with light microscopes you can sometimes swap out the objective lens, but rarely can you swap out the eye piece. Uh. The reason you would swap out the objective lens is

because it does affect the magnification somewhat. A more flat objective lens will have a lower magnification than a rounder objective lens. This is all due to the physics of optics, which I'm not going to go into here because without visual aids, I would be struggling to describe them accurately. The purpose of swapping out those objective lenses is to focus on either larger or smaller areas of a sample.

So if you need to look at really small regions of a sample, you'll want a rounder objective lens, and this will let you look at the very tiny regions of a sample. A comparison microscope is, like I said, a pair of these light microscopes and allows you to view two samples at the same time. That lets you compare those two samples, and you can eliminate the necessity to rely upon memory when comparing one sample with another,

and in the case of forensics, that's incredibly important. You might be comparing a bullet that was retrieved from a crime scene with a bullet that you have fired from a firearm that you suspect was used at that crime scene. So you want to see if these two bullets were in fact fired out of the same firearm, and you want to be able to compare the markings on bullet

one versus bullet Too. But if you were just having to swap them out underneath the same microscope, you would have to remember, all right, well, the markings I saw on bullet one, do they match up to what I'm seeing now in bullet too. With a comparison microscope, you can look at them side by side in real time, and that's much more reliable than looking at one sample than removing it from the microscope, putting in a second sample and then saying, huh, I think this looks the same.

So it it took a lot of ambiguity out of investigation. Now. Light microscopes are really useful, but sometimes you gotta go a little further than what light microscope can do. They have limitations on the amount of magnification they can provide, and that's where you might want to up your game a bit go with something like a scanning electron microscope. Those microscopes can magnify a sample up to three hundred

thousand times. It is an enormous amount of magnification. And a scanning electron microscope can also have depth of field, like really good depth of field, to the point where you will end up with an image that is almost three D in nature. The s c M can or scanning electron microscope can tell researchers a lot about the composition of a sample, so not just what it looks like, but the stuff that it's made out of. So we should talk about how these work because it's simple to

say scanning electron microscope, but what does that really mean. Well, back in two scientists developed a precursor to this, called the transmission electron microscope or t e M, and that microscope would direct a beam of electrons through a sample to create a projectable image. Scanning electron microscopes followed soon afterward. They were developed in nineteen five, just a couple of years later, and initially they didn't get a whole lot

of support in the scientific community. Uh, partly because the transmission electron microscopes that just come out we're already seen to have covered that territory. Scientists are saying, well, why should we spend money developing this new technology. We already have this other one that seems to do the same thing. Ultimately, scanning electron microscope showed that they had features that made

them appealing on their own. So your basic scanning electron microscope consists of the following parts, and it is very different in many ways from a light microscope. You're not looking through an eyepiece the way you would with a light microscope. First of all, the entire guts of the scanning electron microscope are inside a vacuum chamber. The microscope itself is sealed in such a way that there is

a vacuum inside of it. And it has to be like that because you're using electrons as you're scanning medium. You don't want to have any interference from particles or even air molecules. Those could be uh obstacles for an electron beam and it would throw everything off if you in fact had particles or air inside the microscope. So

it needs to be a vacuum. The really important element, actually all of them are really important, but the business element of the scanning electron microscope is the electron gun. These are devices that produce a beam of electrons. It's really not that different from old CRT televisions. Those have electron guns that fire electrons at a phosphorus screen to create the light that you would see on an old television, but in this case, the electron gun creates a beam

of electrons to scan your sample. The most common version of the electron gun that you will find is the thermionic gun, which, as the name implies, has to do with heat, right, thermal thermionic. So you heat up a filament. You typically would use something like tungusten because as a very high melting point, you heat it up really, really really hot. And when you do that, when you pour

energy into it, you help it shed electrons. I've talked about this before, where pouring energy into an atom means that you're energizing those electrons. Electrons typically orbit and atoms nucleus in energy shells, and by boosting the energy of those electrons, they moved to higher and higher shells outside of that nucleus, and if you pour in enough energy, you can strip the electron away from the atom entirely.

So that's what you do with these electron guns. The filament heats up to this incredible temperature and starts to shed off electrons. And then you aim those electrons at a sample. The other type of electron gun, by the way, is the field emission gun, that uses strong electrical fields to strip electrons away from their associated atoms. Electron guns, whether they're thermionic or field emission guns, are located on one end or the other of a scanning electron microscope.

They're either at the very top or at the very bottom. Either way, they're doing the same thing. The lenses in a scanning electron microscope are not optical lenses. They're not ground glass lenses. The lenses in the scanning electron microscope are actually magnets because magnets can shape the path of electrons. Electrons have a charge, so using magnets you can attract or repel electrons. This is how particle accelerators like the

large hadron collider work. They use these powerful electro magnets to control the beam of charged particles protons or electrons. The scanning electron microscope uses magnets to focus the beam of electrons and control them and direct them to where they need to go in order to scan a sample. The scanning electron microscope also has a sample chamber. That's where you actually place the specimen that you are scanning, and since we're talking about crazy levels of magnification here,

you need that sample to be super still. Any movement, any vibration is going to be magnified dramatically and it's going to corrupt your results. So you want it to be very stable, and typically that means insulating it against

all vibrations as much as you can. So if you were to go to visit like a forensics lab, and let's say it's a huge forensics lab, maybe it's an academy, and it's got multiple floors, chances are you're going to find the scanning electron microscopes on the ground floor, because going up more than just the ground floor could potentially introduce vibrations to your sample chamber and that would throw off your results. The scanning electron microscope also has detectors.

Right you're you're blasting a sample with electrons, you have to have detectors to pick up the response of that, and those detectors include stuff like secondary electron detectors. Those are detectors that can actually register electrons from the sample itself. So, in other words, you're bombarding the sample with electrons from your electron beam. Sometimes that dislodges electrons from the surface of the outer surface of the sample, so the secondary

electron detectors can pick those up. But other detectors will include back scatter detectors or X ray detectors. So when you are scanning a specimen, the electron beam moves over the surface of the object, and to do that, the scanning electron microscope uses what are called scanning coils. These are magnetic field generators that use fluctuating voltage to create the magnetic field, and the scanning electron microscope uses that

to manipulate the electron beam. The coils direct the beam across the specimen in a very tight grid like pattern, so up and down, left and right, to get every single point on the surface of that specimen. That does dislodge electrons from the surface of the specimen in unique patterns, so the secondary detector attracts those scattered electrons and then registers those electrons as different levels of brightness on a monitor.

So the intensity of the brightness that you see in the image will correspond with the number of electrons that hit the detector. The detector quote unquote knows where secondary electrons come from based upon the scanning beam's position, and this can be shown in an optical image on a

video display. So think of for for the purposes of visualization, imagine a laser beam it's hitting a single point on a piece of cloth, let's say, And then imagine that you have a sensor that can pick up when electrons are being shot off by this piece of off. So we're thinking of a laser beam as that's the electron beam. We're just imagining it as a laser beam. You move the laser beam across the sample, and the detector is constantly picking up these electrons as they are shot off

by the sample. And because this is all happening at essentially the speed of light, I mean, we're talking super fast, you know where those electrons are coming from, because you know what part of the sample the beam has just made contact with. And that ends up being transmitted to a computer system that interprets that and plots it as pixels points of light on the monitor, and then you get the computer image of what the scanning electron microscope

just scanned. It's pretty darn cool. Backscattered electrons are those from the beam that reflect off the surface of the specimen and a detector can pick up those as well, and in a similar way constructive image. So backscatter. Those are electrons that came from the electron beam, not we're

shed by the sample. And then the X ray detectors pick up X rays that would be emitted from underneath the specimen, and the beam scans the entirety of the specimen and the detector's data is used to construct the corresponding image. And that's how scanning electron microscopes work if you really want to dive more into that technology, because I realized again without visual aids it gets a little challenging to understand. There's a great article on how stuff

works about how scanning electron microscopes work. Now, I'm gonna take a quick break, and when I come back, we're gonna look at some of the other cool technology used in forensic science. Now, in the last episode, I talked about ballistics and measuring stuff like bullet holes to determine the angle and direction of firearm was pointed before firing.

And in the old days you do stuff like tape measures to figure all that out, you know, take physical measurements, but today you typically would use laser scanners, they can give you much more precise information. A laser scanner depends largely on the time of flight method. That's pretty much similar to sonar and radar or speed guns that that police use to detect the speed of a vehicle. The whole idea is what what amount of time does it take for a laser beam to travel from in the

mirror to a sensor. Right, So by knowing the amount of time between when a pulse of lasers left a laser and when they were picked up by a sensor, you can know the distance it traveled. Because it's traveling at the speed of light. That's a constant. You can use that constant and then work backwards and determine how far did this laser beam travel. With laser scanners, you're talking about a detector built into the scanner itself, right,

So they go. You've got an a mitter and a scanner and they're next to each other, and then you take half the distance that you calculate. Because the beam travels out, it hits an object, it travels back and gets picked up by the sensor, So that means the laser has traveled twice the distance between the point of the laser and the the point of contact. So you just take half of that that will tell you the distance. Right.

So you use these laser scanners uh the time of flight scanners, and you move them in a grid fashion to capture all points of a scanned specimen, and then you get this this collection of data points that tells you how far away the various parts of a specimen were compared to the origin spot of the laser scanner. That would allow you to then plot that information in a computer and get a real good read on the

specifics of whatever it was you were scanning. At three D dash forensic dot com, there's a description of this technology used to investigate a shooting crime to have then Vallejo, California. This one took place in there was a couple who were in a car that was outside of a home in California. An argument broke out, presumably between the couple and maybe with someone else as well who was outside the car on a porch in front of the house. That person on that porch fired an a K forty

seven at the vehicle. One of the bullets struck and killed the driver of that vehicle, but the person who shot the a K forty seven later claimed that the passenger of this car had a gun and the passenger was threatening the person who was standing on the porch. So in California, there is something called the provocative act doctrine, which states that if someone incites a killing, if they escalate a situation and then a killing occurs because of

that escalator, that person can be charged with murder. So the passenger in this car could be charged with the murder of the driver of that car because of this provocative act. Even though the passenger in the car wasn't the one who fired the gun, the argument would be because of the passenger's actions, the driver died, so the person charged is not the one who actually did the killing,

but incited the killing to happen. So the prosecution is arguing the passengers actions lead to the death of this driver. And at the heart of the issue was whether the passenger actually did possess a gun and either threatened or perhaps even fired it at the person who was on the porch. The shooter who stood on that porch fired an a K forty seven in full auto mode, which means you just hold down the trigger and it will keep firing until you let go of the trigger, You're

out of bullets. Investigators were brought in to answer quite is, like where was the car when it was struck by the two bullets? What is the line of sight from the porch of the house to the position of the car. If you assume the height of the person on the porches about five ft eight inches, that was the height

of the shooter. What is the line of sight from the front passenger position to the porch, Because if the person in the passenger seat was actually threatening the person on the porch, they would have to be able to see that person. Was the vehicle in motion? If so, how fast was it going? And could the investigators determine the order of the two bullets that struck the car? Which one was first? The three D laser scan that the investigators used, uh, they made one of the bullet holes,

they did of the car, the porch. They actually scanned the whole area, but they were looking at the bullet holes first, and that indicated that the two bullets that were both shot from the same angle, which indicated that the shooters stood in the same spot while firing the shots. But there were there was a distance between bullet hole number one and bullet hole number two, and that distance would mean that the car must have moved two point

seven feet between those two shots. And the reason they realized that the car was the one that moved and not the person was because the a K forty seven was fired in full auto mode. The time between two shots from a cold start would be about one tenth of a second, which means the car must have moved to get two point seven feet further in one tenth of a second. That's way too fast for a person to have moved and been able to fire this gun, and it would mean that the car was moving at

around a little less than twenty miles per hour. The investigators ended up conducting thorough laser scans not just in the vehicle, but the whole area where the crime occurred, and at the heart of the issue was conflicting testimony. Did the passenger have a gun? Was the passenger threatening

or actively shooting the person on the porch? And based on the scans and simulations, the jury found the evidence did not support the shooters claim that the passenger was threatening the shooter with a gun, and so the charges of murder against the passenger were dismissed. So that's kind of an interesting way of using laser scanners. It's a

pretty fascinating discussion. And again, if you go to that website three D dash forensic dot com, you can find the whole case study written up and in greater detail and learn more about it. So let's say let's change gears a little bit. Let's say you go to a crime scene and there's broken glass everywhere, and the cops have a suspect and custody, and a close examination of the suspect's clothing revealed that there were some glass particles

that were attached to that clothing. They were they were just stuck on there. But the particles are really small, and it's not obvious that they come from the crime scene. They might be unrelated. So if you've got really small glass particles, they're so small that you can't just you know, piece them together, how can you determine whether or not they came from the crime scene. Well, you could call in the laser ablation inductively coupled plasma mass spectrometry device.

It's also known as the l A I C p MS. One of those cases where the acronym is almost as clunky as the full name. It sounds like something out of Ghostbusters, doesn't it. But this is a Once you break it down into its component parts, it's a lot easier to understand because when you hear laser ablation inductively coupled plasma mass spectrometry, that seems like it would be insane, but it actually makes a lot more sense when you break it down. So first, let's talk about laser ablation.

This is where you use a laser beam that is of a particular strength so that when you move it across a sample surface, it generates fine particles. Through laser ablation, essentially, you're shaving off particles from the sample. You gather these particles and they go into a chamber where an inductively coupled plasma instrument otherwise known as a plasma torch ionizes the particles. Once again, you uh impart a lot of energy to the particles, so it ends up ionizing them.

It sheds electrons, it becomes charged, and then you put it through a spectrometer. The spectrometer separates the ions using filters, which aren't physical filters. It's not like a mesh or something. There in the form of first an electric field and then a magnetic field, and this forces the ions to fan out into a spectrum, and the ions will all fan out based upon physical uh features of those ions, So all like ions will end up in one part of the spectrum and unlike ions will be in a

different part of the spectrum. So by looking at the whole spread of the spectrum, you can say what that substance was made out of. A detector will count up the ions and the various parts of the spectrum, and a computer program analyzes the results to tell you what

it was that you zapped. And by analyzing a sample from a crime scene and then comparing those results to samples collected from a suspect, you can see if the glass was made out of the same stuff, and if it is, that's a clue that your suspect is someone to look at very carefully, as that match suggests that they must have come in contact with the crime scene. Now it's not it's not like smoking gun evidence, but it certainly suggests if there's a match, that they were

involved in some way. Uh. If there's not a match, then you could say, well, according to our results the glass, Yes, you found glass on this person's clothing, but it doesn't match the glass that was found at the crime scene, so we can't say for certain that there was any connection there. That actually suggests there's not a connection. Then

we can move on to stuff like document examination. This is where you're looking for, uh, any evidence that was left behind in kind of writing form, whether it was you know, handwriting or typing or printers whatever that maybe. And this can be used in all sorts of crimes, not just the kind of violent crimes I've sort of talked about before, but all certainly like corporate crimes, you know, that kind of stuff. So there's a lot of different

ways of doing this. One way is to look for indented writing, you know, the idea that there's traces of someone having written something. It's not necessarily on a piece of paper. They're looking at maybe a piece of paper that was underneath the one that was being written on. Typically you would want to use something like oblique light

and photography first. In other words, you're hitting the surface of the material that you suspect has indentations from previous writing with light from different angles in order to try and illuminate those indentations, and then you take pictures of it. But there's also a device called an electrostatic detection apparatus or E s d A that you can use. And you know, when you write on a top sheet of paper.

Let's say you've got a pad of paper and you're writing on that top sheet, you might see that you've got indentations on the lower sheets and uh, and you would use a pencil to shade out those indentations to read writing. You see that in a lot of detective shows, right a detective sees a pad of paper next to a phone, picks up the pad of paper, grabs a pencil, shades the pencil across the pad of paper, and spells how the message like see pick up bag at third

and Broad Street or something like that. And you're like, oh, okay, well voila. E s d A takes a slightly more electrifying approach to this concept. So an E s d A device generates an electro static field, and think of it like, you know, uh, static electricity, that idea of building up this charge. It imparts this electrostatic charge to a document that could have indentations on it. So these

machines have a platform made out of bronze plate. You put the piece of paper you're gonna scan on top of that bronze plate on top of the piece of paper, you put a thin layer of film on there, and then you pass a highly charged wire called a corona over the paper. And it's this highly charged wire that imparts an electrostatic charge to the paper underneath. The indented parts of the paper received the largest amount of that

electro static charge. Then once that's over, they can expose the film covered paper to toner, and the toner also has an electrostatic charge, but it's opposite to the charge that the corona gave the paper, and opposite charges a tract So the indented spots with the greatest amount of charge attract the toner. Then you can see where the invitations were. You can see them more clearly. You might

be able to read stuff. It's really not that different from the way a photocopier works, if you remember my episodes about that. So I thought that was a pretty cool technology. Sometimes, however, you're not just looking for evidence that someone has actually written something on a piece of paper. You might want to determine if a document has been altered.

For example, let's say someone's signed a contract and then later on they come to a court and they say the contract I signed is different from the one that they claim I signed. They must have changed it after I signed it. They might want to use something like a video spectral comparator device what the heck also called

a VSC. So this is an imaging device. It combines multiple cameras, multiple sensors, and different lights to examine a document and the entire spectrum of light, including ultra violet and infrared that's beyond the visit spectrum, right We humans can't see that without technological aid, so a computer is able to render the results in shades we can see.

So you've got these cameras that can pick up in these different frequencies, You've got lights in these different frequencies, and sensors in these different frequencies, and through all this you can analyze the data coming back and a computer can present it in a way that we can actually see. And the analysis of color is really important as it can detect when two different but similar incs were used on a document. So to our eyes, we might look at the document and say, well, this was clearly all

written at the same time. We can put it through a an analysis like this, where you're using different wavelengths of light to analyze the document, and by taking precise measurements of the light that's coming off that document that's being reflected back from that document, you could say, well, actually, it turns out there are two different inks that were used on this document, which indicates that there were as, there was a point where it stopped and started up,

and it was printed on a different device, and uh so to casual glance, it might look like this was all done at once, but you could say, well, no, the analysis shows there's two different inks here. They look the same to our human eyes, but when we put it through the vs C, we can clearly see that there were two different types of ink. So it's really helpful if you want to see if in fact the document has been changed, if something has been erased or replaced.

Very interesting technology. Well, I've got some more that I want to talk about in the great world of forensic tech. But before I get to that, let's take another quick break to thank our sponsors. I just talked a bit about devices that use cameras. Might as well stick with cameras because photography is a really important part of forensic science. Let's say there's a case where a forensic nurse, and

there are such things. A forensic nurse is called in to treat someone who appears to be the victim of a physical attack. This person might not be communicative, and this can be a matter of life and death. And sometimes evidence of physical harm is hard to see, particularly if that harm happened just a short time earlier. So uh, for example, there might not be evidence of bruising that it's that's visibly. Uh, they're right, but there may very

well be damaged that will lead to that. So there are cameras that make use of a technology called alternative light source photography that can reveal evidence of physical harms such as bruising, before they become visible, and it allows medical staff to treat a person quickly, and sometimes that

can be the difference between saving someone and losing them. Now, it's called alternative light source photography because those cameras may use something like infrared light or ultra violet light, or they might even use visible light, but it's in a

very particular wavelength. For example, I saw one version of such a camera that uses blue light to illuminate a person's skin and then has a special orange filter to try and pick up any evidence of physical harm that might not be visible under normal lighting conditions, which I thought was really interesting. They're also high speed cameras that are frequently used to get a better understanding of ballistics evidence.

High speed cameras can take images at incredible speeds, as the name suggests, and typically that requires a lot of light. You don't really use high speed cameras and low light conditions, and that's because cameras work by focusing light coming through a lens through an opening called the aperture, which can open or shrink. If you open, you allow more light to come through. If you shrink, you allow less light

to come through. And you have a shutter. The shutter is a device that opens and closes and allows the light to either pass through and expose an image on film, or it hits a digital sensor, right for for digital photography. With high speed photography, this has to happen really really fast.

Right You're you're creating images at an incredible rate, So the shutter has to be able to open and close super super fast, and that means you have to have a very well lit scene because the shutter is just allowing light through or not allowing light through, and if it's moving super super fast, not a whole lot of light gets through on each time it opens, So you want to have a very bright scene in order to

be able to see anything. Otherwise the video or film that you take is going to be very very dark. There's also a thing called a gunshot residue scanning electron microscope as another detection tool that can help look for a gunshot residue. No big surprise based on the name. It's actually a combination of hardware in software, and typically these things look like big desktop computers, you know, with

a couple of monitors, big tower. There might be some specialized peripherals attached to it, but you know, if you looked at a casual glance, you might just say, oh, that's just a desktop computer. The microscope works like the scanning electron microscopes i mentioned earlier, looking for any suspicious particles that could be the residue from a firearm discharging, and then the system uses spectroscopy to identify what those

particles are. So both the technologies are referred to earlier in this episode would be combined in this kind of approach to first look at very closely a material that you suspect might have gunshot residue on it, and then through spectroscopy, do this analysis to determine are there, in fact any particles there that would indicate gunshot residue. On TV and movies, we often see investigators using technology like

three D facial reconstruction technology UH. The technique uses algorithms to determine what someone might have looked like based upon typically remains. It's pretty grim stuff, so you find remains at a scene, maybe you find skeletal remains, and you wonder what did the person look like in life, and you're trying to reconstruct that that That technology really does exist, though it has shown to be variable in its reliability

depending upon the actual implementation. It doesn't always work perfectly,

and it depends heavily upon the software packages that you use. Typically, you would use software UH to analyze a scan of the remains, So you're using scanners to completely get a very detailed representation of those remains, and the software would then go over that information, and you might also have to include other information you might have about the person, like if you know anything about their age, their gender, UH,

their ancestry. All of that could be taken into account by the software package while it's trying to build out what the person might have looked like, uh, in life. And then you might feed the software some images of say, missing persons. Let's say that you've got a file of

people who have gone missing. You might feed those images through to see if the computer system can find any matches between the reconstruction that's created and any actual humans that you have pictures of, and if there are any matches that would allow you to help narrow down your investigation. Potentially, it doesn't. Again, it's not necessarily a hit, but it could mean that you are you've got a lead to follow.

As I said, the reliability of the software depends upon the actual software package used, so it's it's not infallible. We also see a lot of news about DNA evidence, which is really important stuff. Let's say you recover some DNA evidence at a crime scene that doesn't match any of the known people to have been there, right, so

what or it's a violent crime or not. You find some DNA evidence, you've eliminated the people who typically are at that place, and you want to know who the heck does this DNA belong to, It could belong to the perpetrator of a crime. So you take the DNA in for analysis. You first replicate that DNA millions of times for the purposes of testing, so that you have enough of it to work with, and then you analyze it.

And scientists can use phenotyping to identify genetic markers and DNA variants and based upon that information make predictions about the appearance of the person who that DNA belongs to. These predictions are very general, so they're also based off probabilities. Nothing is totally certain. You can't just scan the DNA and say, ah, I know exactly what this person looks like, but you can get some general predictions. There's a couple

of different systems that can do this. There's one in particular, the hi risplex system that I read about. According to what I read, it can predict blonde hair. Uh. If it's got the markers for blonde hair, it can predict whether the person has blonde hair about sixty nine five percent at the time. Now, blonde hair that's carried by a recessive gene, it's not really surprising that the success

rate is below. Brown hair gets a much higher hit rate at seventy eight point five percent, red hair even higher at eight percent, and black hair gets the highest

at eighty seven point five. The system can also use the same sort of methodology to predict what color eyes the person probably has, and so then if that's all you have to go on, if there are no why witnesses, but you have some DNA evidence, you could say, well, based upon our analysis, there's the x amount of chance the person has brown hair and blue eyes, and so that at least gives you some parameters you can start to look for when you're doing your investigation, although again

you have to remember these are all based on probabilities, not certainties. And this next one goes out to all you gamers out there. We live in an age where there are numerous ways to store electronic data. You might have a computer, a smartphone, a tablet, USB drives, hard drives, optical discs. If you're clinging to the past, you might

use cloud storage. But one device that sometimes can be used to store incriminating information is the good old game console like the Xbox, and a moded Xbox can be used to store all sorts of information of questionable legality, not to mention stuff that's just outright illegal, and uh mods can exploit known vulnerabilities in the Xbox. You don't necessarily have to crack the Xbox open and do some

soldering to change things. There was one example that was cited in a paper titled x f T, a Forensic Analysis Tool for the Microsoft Xbox Game Console. It was written by a guy named David Collins, and he pointed out that there was an Xbox game Double O seven Agent under Fire that had a vulnerability. An Xbox owner could visit a link and download an exploit that was created by a hacker. The exploit used the buffer overrun

vulnerability in that game for the saving process. So on the Xbox, it would look like it was a valid saved game. That's what the file would look like. It's like, oh, well, that's just that's just a save game file, But in reality it would be an operating environment. The Xbox owner could use that operating environment to browse files using the FTP protocol and download files to the Xbox and the guys of this save file, so on casual glance, it

wouldn't look like anything was hinky. Now, the Xbox used a file system called f a t X that is not readable by most forensic software. So let's say you're on an investigation and you want to check the Xbox for any illegal information. It might not be readily apparent that such information is on that Xbox if you don't know where to look, and you can't easily scan it with most forensic software. So digital forensics experts developed a tool called the x f T, which is a command

line utility. It behaves like a Linux shell and allows an investigator to image the file system of an Xbox, which then would allow an analyst to browse the contents on the game console in the search for illegal material. And it can record a browse session so that prosecutors could present that to jurors in a trial to show exactly where a criminal hid data on the game system. Now, one forensic tool I think is really neat is actually not high tech at all. It's actually pretty low tech.

But that's kind of why I like it. It's so elegant, and it's the use of magnetic fingerprint powder and magnetic wands. Sounds very hairy potter ish, but it's not the powder. The magnetic powder. It's dark. It can be used as you know dark powder, black powder that you would typically use when dusting for prints, but this particular powder contains iron filings in it, which means it's attracted to magnets. So when you want to dust a surface for prints,

you take out the magnetic wand. Now this is essentially a plastic cylinder, and there's a cap on one end of this plastic cylinder. It's got an end on a capped end. Inside the cylinder is a magnet that's on the end of a plunger. So if you push the plunger all the way down, the magnet is pressed up against the back end of that cap, the inside of

the cap. Then you can use the wand to pick up the magnetic powder and it's going to clump to the end of the wand you would then gently move the wand across the surface that you are dusting for prints, and you would use it like it's a brush, except instead of it being the bristles of a brush, it's actually the magnetic powder itself. And you're not letting the

wand contact the paper, it's just the powder. So as you do this, some of the magnetic powder comes loose, and if their fingerprints on the surface, the powder will reveal the presence of those fingerprints. Once you're done brushing the surface, you can then move the wand back over to the container of magnetic powder. You position the wand over the contain inner so that you're being nice and careful and neat, and then you pull the plunger back

up the length of the cylinder. This moves the magnet away from that capped end, and the magnetic powder will just fall freely down into the container because there's no longer that they're no longer close enough to the magnetic field to be attracted to it anymore. One thing that you do have to take into account if you're using this stuff is it is more abrasive than normal black powder,

so brushing has to be very gentle. As for future technologies and forensics, we might see investigators look at stuff like the microbiomes we carry with us, those those or those kind of cultures of micro organisms that are unique to us. No two people have the same microbiomes, although sexual contact can intermingle the microbiomes of one person and another.

In fact, an investigation could reveal that. So say it's a it's a case where someone is coming forward and they have an accusation and in volves sexual assault, then investigation of the microbiome might be one of the ways you could confirm that uh it. So being able to identify and classify microbioms could become a really important investigative tool in cases where you may not have a good DNA sample to work with. UH. For that to happen, that scientists have to prove that it's a reliable way

of identifying a person. UH that they have to show that it is in fact something that you could base a legal case on and it's so they have to show that it's it's a verifiable and reliable technology. Another line of investigation might focus on pollen particles that can indicate specific travel patterns people have taken based upon the pollen they've come in contact with and they have on

their clothes or skin. The study of pollen is called palein ology p A L Y N O L O g Y. It's pretty hefty stuff because there are a hun ords of thousands of species of flowering plants out there, so it is not easy to identify pollen UH necessarily, but it could be a promising addition to the forensic investigators growing collection of tools and strategies. And there's other

stuff that didn't talk about. I mean, there's stuff where you could look at the computer system on a car to look for uh, indications of things that you might suspect based upon a crime that might have been committed

by someone driving. There's a lot of different avenues of investigation out there, and honestly, I could do a full podcast series about these, but I thought it was interesting to kind of give this this look into what's being used today and the technologies that might be used tomorrow. Uh So thanks a lot Hakim who asked us to look into this, I greatly appreciate it. If you have a suggestion for a future episodes tech stuff, why not, right and let me know what that is. The addresses

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