The New Detectives

Often, the eyewitnesses of a crime are also the main suspects. They're able to manipulate the truth to throw off the authorities. When a murder is committed and deceit clouds the evidence, investigators turn to forensics to uncover the truth, expose a murderous lie and capture the killer.

In criminal investigations, a simple clue can provide the missing link by placing a suspect at the scene of the crime. Dirt left on shoes, tires or clothes can pinpoint where the crime occurred. But it takes the skilled eye of a forensic investigator to follow the trail of evidence to find the killer.

Approximately 1.8 million Americans are reported missing each year. Some are runaways who find their way home, but others simply disappear. When foul play is suspected, investigators turn to forensics to find the missing.

Bombers, snipers, spree killers: some people don't care who they kill, they just want to hurt innocent people. These killers are the hardest to catch because they have no connection with their victims, who are just in the wrong place at the wrong time. But even random bloodshed leaves traces at the scene that can direct an investigation and stop the killer before he can strike again.

Investigators use forensics to solve relationship tragedies.

Police use trace evidence and paint analysis to track a killer of gay prostitutes; a husband is linked to his estranged wife's murder by saliva and ink found at the scene.

Poison is an almost invisible form of death and is often interpreted as a heart attack or underlying health issue. But when foul play is suspected, toxicologists must look for hidden clues in blood and tissue to bring these murders to light.

Some people do get away with murder, at least for a while. Thrilled by their success, they tend to kill again and again. But with each crime they leave behind more clues for investigators. In this episode, two serial killers are profiled: Faryion Edward Wardrip who murdered five women in Texas, and landlady Dorothy Apuente, who murdered seven of her tenants.

At the scene of a murder, sometimes the only clues to the killer come from the victim. Forensic anthropologists use skeletal remains to decipher the clues written in the bones to bring the murderers to justice.

Time of death is an important consideration in a murder investigation but when a killer freezes, burns or even grinds his victim, even the most expert medical examiner would be at a loss about how to calculate a time frame. Forensics has its own techniques to solving these grisly crimes.

Accidental deaths, suicides, disappearances and fires: they're an everyday part of an insurance investigator's job. But these cases shouldn't be taken at face value. Forensics has become a vital tool in exposing insurance fraud.

Drowning deaths often look like accidents and over time water can destroy the few clues the killer may have left behind. Investigators must turn to forensic science to solve homicides in which the victims were found in bodies of water.

The elements of nature can reduce a body to bones in a matter of weeks. Combining art and science, forensic anthropologists can give victims a face long after they've been forgotten.

Dogs have been trained to sniff out corpses, drugs, explosives, and missing persons.