F2: Forensic Factor - Season 4

Between January 1994 and April 1996, in central Florida, the bodies of four men are found in a wooded area known as The Hog Trails. All are severely decomposed, all are naked, and all have been genitally mutilated. Police realize they are chasing a serial killer, but the investigation is hampered by the fact that they are unable to identify any of the victims. Finally a fifth body yields a name.

For 23 days in October 2002 a sniper terrorizes the Washington DC area, shooting thirteen people and killing ten. The victims are ordinary people doing routine activities. Nothing links them; they are chosen at random. Police mount one of the largest investigations in American history to catch a ruthless and elusive killer. In the end, their most productive clue comes from the sniper himself.

Carole Sund, her daughter Juli and friend Silvina Pelosso go missing while vacationing in Yosemite National Park. The theory is that they had a car accident. What begins as a search and rescue operation becomes a chilling case of murder when the bodies of two of the women are discovered in the trunk of their burned-out rental car.

A retired fireman on a morning bike ride notices a burning bundle in a farmer's field...and recognizes the smell of burning human flesh. Investigators at the scene find an unrecognizable body, a distinctive lighter, 2 pairs of latex gloves and the box they came in, paper towels and torn scraps of an office memo.

April 1992. An elderly couple is found dead in the trunk of their car at their home in upscale Toronto. The investigation eventually leads authorities to the couple's vacation home one hour north of the city. Police soon learn of the "House Hermit" - a mysterious intruder breaking into area cottages and camping in them. He becomes the prime suspect in the murders.

The 1996 Summer Olympics in Atlanta, Georgia are rocked by a massive pipe bomb explosion. A woman is killed, and hundreds injured. Subsequent bombs at an abortion clinic and a gay bar show a similar M.O. and increasing refinement. Police have no clue who is behind the bombings until they receive a letter signed by 'The Army of God', an anti-abortion, anti-gay, white supremacist group.