From Green River Killer, Gary Leon Ridgway to Ted Bundy to Harold Shipman and more, experts on serial killers tell A&E True Crime who was the 'worst' serial killer and why.

Marcia Clark of 'Marcia Clark Investigates the First 48' tells A&E True Crime why she was interested in investigating the mysterious death of Rebecca Zahau on the show.

Convicted murderer Adnan Syed, subject of the wildly popular podcast Serial, has been granted a new trial. Here are details on what led to Syed's controversial conviction and what we know about the upcoming trial.

As smart technology advances, so does the means for authorities to detect crime. A&E True Crime looks at some of the more memorable cases of criminal clues in the Wi-Fi age.

Marcia Clark of 'Marcia Clark Investigates the First 48' tells A&E True Crime what swayed her in determining who was really at fault for Bonny Lee Bakley's death.

Journalist and therapist Nikki Meredith has corresponded with two of Charles Manson's most infamous followers for decades: convicted murderers Leslie Van Houten and Patricia Krenwinkel. Meredith spoke with us about what the former cult members are like today.

Psychologist Al Carlisle, who was part of a diagnostic team at Utah State Prison who evaluated Ted Bundy, talks about the serial killer's lonely childhood, participation in illegal activities at a young age and strong desire to control women, which Carlisle believes led to his psychopathic tendencies as an adult.

Prosecutor Marcia Clark of 'Marcia Clark Investigates the First 48' on the negative effect the media had on the investigation into what really happened to Chandra Levy.

True-crime author Harold Schechter, author of 'Hell's Princess: The Mystery of Belle Gunness, Butcher of Men,' on what made serial killer Belle Gunness unique and if she tricked everyone into believing she died.

In 1991, four teenage girls were brutally murdered in a yogurt shop in Austin, Texas. The killers have never been caught and the crime has never been solved.