All Signs Point to Innocent

Identifying all of the skeletons found under Gacy's house will take years, but by reading the clues in the bones, forensic anthropologists can tell what kind of person the Killer Clown targeted.

In the first case using ballistic evidence, the validity of ballistics as a forensic science was called into question when an "expert witness" lied on the stand and sent an innocent man to death row.

Join executive producer Annie Paterno and director Jay Dahl on the set of Catching Killers to see how recreating an investigation is all about the details - right down to the clunky computers and office supplies.

With only tiny insect fragments from the radiator in Vincent Brothers' car, bug experts can prove his alibi is a lie.

In 1983, police in Leicestershire, England struggle to make their case - until they join forces with scientists, who are just discovering the potential of DNA profiling.

In 1935, when decomposing body parts were found under a bridge, maggots were used to determine time-of-death and bugs became evidence for the first time.

From cradle to grave, no matter how much fingers grow, everyone's fingerprints are unique and unchanging.

In 1840, a murder case hinges on whether a man died of cholera or arsenic-poisoning, and for the first time ever, scientists are called in to test his remains.

Forensic investigation is nothing new to Smithsonian's National Museum of Natural History. Their collection of donated human skeletons has been used to solve crimes.

After multiple shootings, the only evidence in the DC Sniper case are bullet fragments pulled from the victims. Luckily, scientists can use those to answer vital questions about the killer's weapon.