Forensic Files
Scratching the Surface (7x33)
: 24, 2003
In Miami, Florida, a sniper opened fire from the rooftop of a manufacturing plant, killing one employee and injuring two others in the parking lot below. When the gun was found, the police discovered that the shooter had scratched the serial number off of it to make it untraceable. But forensic scientists had a way to make the number reappear. Originally aired as Season 7, Episode 33.