Catching Killers: SEASON 2: EPISODE 5

Trace Evidence

Hair, skin cells, fibers, residue, and specs of dust. Sherlock Holmes and his magnifying glass made the analysis of trace evidence famous, but French scientist Edmond Locard made it a movement. Discover how his bold theories on using microscopic evidence to solve crimes helped crack a high profile murder case in 1912. Then travel forward nearly 80 years to discover the trace evidence that was the only hope of catching California's notorious "I-5 Strangler." Two big cases, each solved by evidence barely visible to the naked eye.