"Where's The Rest of The Blood?" Forensic Expert Talks DNA at Nancy Guthrie Crime Scene

Now that we know the black glove did not come back with a DNA hit, what's next in the Guthrie Investigation? Investigators are working on leads from the Nest doorbell cam, finding out who purchased the intruder's clothes and backpack from Walmart, and any information from Nancy Guthrie's pacemaker.

When Investigative Reporter Anne Emerson spoke to a forensic expert about the possibility a blue light was brought back into the crime scene, Dr. Laura Pettler wanted to know, "Where was the rest of that blood?" Anne and Dr. Laura takes us through the crime scene once again with what we know and what we don't know and go through a forensic checklist three weeks into this investigation at Guthrie's Tucson home.