The use of the computers by law enforcement is detailed in this look at a series of crimes in St. Louis that stumped the local police and the FBI. (also marked as S7:E44)

Authorities are able to apprehend a kidnapper because he allowed his victim, 17-year-old Shari Smith, to write a will on a telltale pad of paper. [also marked as S7:E52]

In Dripping Springs, TX, March 1999, a 3-year-old boy develops serious respiratory problems and then his father later shows signs of early Alzheimer's disease. A chance encounter with a stranger kicks off an investigation into the cause. [also marked as S7:E19]

Firefighter Michelle Baker became pregnant by her lover, Dr. Maynard Muntzing. After this news, she was ill whenever they were together. The coincidences led her to suspect that he was doing her harm, so she set out to prove it.

In Texas 1988, Nancy DePriest was raped and murdered while working at Pizza Hut. After a suspect confessed and implicated another, they were both imprisoned; the case was considered closed. Eight years later, another man claims that he committed the crime, and investigators must use forensic evidence to determine the true killer.

In a small South Carolina town in 1991, 17-year-old Crystal Faye Todd, a popular high school student, is raped, murdered and dumped in a deserted field, after attending a party. With few leads, authorities test the DNA of several friends and one match shocks everyone.

A look back at a trio of unsolved murders that occurred in Wichita Falls, Texas during the 1980s, details how a fourth murder from the same time period provided the police with more than they realized. John Little, an investigator for the DA's office, picked up the cold cases years later and made a connection to the other murders.

The disappearance of 6-year-old Michelle Lee Dorr is detailed. Although her father confessed to murdering her, the police soon poked holes in his story, leaving the case unsolved for 14 years. New suspect Hadden Clark was heard talking to himself, which gave investigators a clue where Michelle was killed.

Exploring how an American hit single from 1966 -- the cheater by Bob Kuban And The In-man -- foreshadowed the demise of the group's lead singer, Walter Scott (Walter Notheis Jr.), who disappeared in 1983.

The disappearance of Philadelphia college athlete Aimee Willard is investigated after her car was found, still running on the roadside. When her body is found, the police find unusual marks on her body and DNA evidence that eventually lead to her killer.

The 1991 disappearance of Newport Beach, CA, resident Denise Huber stumps investigators. Three years later, Arizona residents call police to report John Famalaro, who has kept a Ryder rental truck in his driveway, which they suspect is stolen. Upon further investigation, police find a body within a freezer inside the truck, which they conclude is Denise Huber.

When a 62-year-old man opens a car restoration business and becomes seriously ill, his doctors cannot find the cause, but forensics can; identification of a highly toxic metal in the victim's blood leads to his poisoner.

A serial arsonist is responsible for numerous fires that caused millions of dollars worth of property damage and the deaths of three people - described as the worst arson spree in US history. More than 75 Seattle-area arsons are probed before he was discovered, partly through the use of forensic hypnosis.

In 1995, Madalyn Murray O'Hair, the founder of American Atheists, disappears along with one of her sons, her granddaughter, and $500,000 in gold coins. The discovery of a mutilated body helps police catch the culprit.

Details the case of the Beltway sniper attacks, a 3-week shooting spree which left 10 people dead in the Washington, D.C. area.

Although a group of teenage thugs are suspected of attacking two boys on a fishing trip, there is no solid evidence until a murky fishing hole provides some answers.

A look into the 1984 Oregon food poisonings, we're detectives track down the outbreak to a cult which aims to use germ warfare to take down the government. [also marked as S7:E16]

A look back at the case of the River Park Rapist, who sexually assaulted four women in South Bend, IN, during 1996. Law enforcement officers arrested Richard Alexander, who was convicted in 1998 and sentenced to 70 years in prison. In 2001, Michael Murphy confessed to one of the two rapes of which Alexander had been convicted and forensic developments reveal new facts about the case.

The 1996 Seattle murder of suburban couple Raquel Rivera and Jay Johnson is detailed. Investigators first believe the slayings were the result of a drug deal gone bad. However, no drugs are found in the house and the victims' blood isn't present on the clothing of the suspects. Evidence from the couple's dog Chief, who was also killed, eventually ties one of the murderers to the scene. This is one of the first cases where dog DNA was used to convict.

Using an anonymous letter and geographic profiling, investigators in Philadelphia close in on a serial rapist who attacks victims who live on upper floors of apartment buildings. When they hear of similar cases in Colorado, a cleverly obtained DNA sample confirms their suspicions. [also marked as S7:E18]

In 1994, on Canada's Prince Edward Island, the body of Douglas Beamish's estranged wife, Shirley Duguay, was discovered. In a groundbreaking case using animal dna, investigators use forensic testing on a cat to help them solve the case.

In January 2001, in Duluth, MN, two people witness a truck driving over an unconscious man twice, and they flee into a nearby bar. When the police turn up, the truck, the victim and the witnesses are gone. The eyewitnesses may hold the key to the death of motorcycle gang member, Erik Schrieffer.

The 1987 disappearance of Houston resident Tracy Jo Shine is recalled. The investigation went cold until 2000, when a "cold case squad" learned that the woman's ex-boyfriend Michael Neal had bragged about killing her.

n 1994, friends reported that Jack Reeves' mail-order bride Emelita Villa had disappeared. The police centered their suspicions on Reeves and, while pursuing leads, uncovered information linking him to the deaths of two former wives.

The murders of an elderly couple, Edward Kowalzck and Gertrude Thompson, leave detectives stumped until, two years later, they receive a major break. A jeweler looking through old newspaper clippings recognizes a necklace the female victim wore as having been pawned in her own shop. [also marked as S7:E14]