Forensic psychologists delve into the minds of serial killers, explaining why, most often, they can be a friendly neighbor or a tenacious co-worker – the ones who hide their darkness better than anyone else.

It is difficult to convict a murderer if the body can’t be found, but forensic science is finding ways to do it. A speck of blood, a piece of a fingernail or a strand of hair may now be enough evidence to prove a murder and capture a killer.

Observing how the smallest bits of forensic evidence, such as carpet fiber or an eyelash, can seal a case. Included: how strands of hair indicted a killer.

Plants help provide oxygen and nutrients for existence. In criminal investigations, a simple seedpod can provide the missing link by placing a suspect at a crime scene. Dirt left on shoes, tires or clothes can pinpoint a crime scene.

While drugs can cure disease and ease pain, they can also be agents of murder. Toxicologists can examine blood and tissue to uncover cases where death is not as natural as it may seem – from slow arsenic poisoning to quick cocaine overdoses.

A tool used to commit a crime can often be the same tool used to solve it. The pattern a machine leaves on an item, the unusual way a tool crimps a wire and even something as innocuous as the shape of a wood chip can lead to a killer.

Advancement in science and technology are encouraging people to revisit the past in hopes of answering questions that have remained unanswered. Techniques from the 20th century are applied to cases dating back as far as ancient times.

Investigators are always on the cutting edge of new forensic techniques that can help them solve cases more accurately. Advanced techniques allow crime solving to take on a new dimension, providing safer and more efficient ways to capture criminals.

Insurance torchings, mob burnouts and arson murders: these crimes are designed to take all clues with them. But a case can be built from ashes. Arson investigators do everything from gathering physical evidence to mounting undercover operations.

Because of new technologies, terrorism is a growing international threat. With the expertise of bomb squads, chemists and tool mark experts, bombs are deactivated and criminals are caught.

Time of death is an important consideration in an investigation but when a killer destroys the body, even the best medical examiner would be at a loss about how to calculate death's time frame. Forensics has its own techniques for solving these 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.

When theft is committed, something valuable is stolen. But when a criminal needs a new identity, theft becomes lethal.

Photography has long been a fundamental tool in homicide investigations. A single image can hold enough information to identify a suspect and preserve vital clues long after a witness’s memory fades.

When murderers hide or destroy the remains of their victims, forensic scientists must reconstruct the scenes and prove murder for an absent witness.

Coroners play a vital role in piecing together the final moments of someone’s life. Los Angeles County coroner Julie Wilson provides an in-depth look into the science of death, as well as the techniques and methodology used by coroner investigators.

A house fire in California turns into a murder investigation when authorities discover that the victim’s best friend and personal manager had recently cleaned out her bank account.

Often, criminals misuse the trust they’ve built with their victims to commit heinous misdeeds. A family discovers the mummified remains of a pregnant woman; a nurse notices an unusually high number of deaths in an ICU unit and suspects foul play.

Contract killings allow someone to establish the perfect alibi. By hiring someone else to do his or her dirty work, a person can deflect guilt or twist the truth. Forensics is changing that, leading investigators to the employers of killers.

A murdered woman is found stuffed in the boot of her car, and a routine investigation reveals a wife may not have abandoned her family on purpose. When everyday substances reveal hidden clues that break a homicide case, those substances become the elements of murder.

There’s an old saying that a burden shared is a burden halved. But when people team up to commit murder, the weight of their guilt remains just as heavy. Investigators must rely on forensic science to capture partners in crime.

What does it take to prove murder if the victim cannot be found? Forensic investigators must go to great lengths to catch the killer when the victim is only presumed dead.

Poisoners are the most dangerous culprits in the crime world: smart assassins. They rely on their devious stealth and must put their victims at ease to earn their trust. And, usually, they don’t stop at just one victim.

The Texas Rangers were established in the 1800s to protect settlers from Native Americans. That role has evolved greatly over time to keep up with a changing society. Today, their job includes solving murders with advanced forensics labs.