Motive to Murder

In 2011, a gunman kills six and wounds 13, targeting Congresswoman Gabrielle Giffords in Arizona. Police arrest a disturbed 22-year-old with a history of alarming behavior.

A grandfather's disappearance in rural Utah leads to a multi-state search, uncovering a shocking murder by a father-son duo.

A teen's murder in Mansfield, Texas, reveals a chilling tale of obsession, revenge, and a love triangle.

In Houston, a brutal crime scene leads police to a petite woman who claims to find sexual satisfaction in killing.

Two robbers kill five employees at a Wendy's in Queens, New York, leaving two others for dead. A survivor's testimony unveils a story of revenge and betrayal.

A drug-fueled killing spree terrorizes a small California town, where police uncover two childhood friends who kill for thrills.

In an Australian town, bodies of women are found with strange marks, leading police to a 20-year-old man who claims to be following a "sign" to kill.

In 1986 LA, over 50 African-American women are found dead, dumped in the trash. The killer is caught when he is seen pushing his latest victim in a shopping cart through the streets.

A police reservist finds a mass grave near Johannesburg, linked to a child advocacy leader who targets women resembling a mystery woman from his past.

A homeless man finds body parts in a North London dumpster, leading police to a killer. The case breaks when a suspect's door reveals weapons and a dismembered victim.

For decades, Italy fears the cold-blooded Mafia hitman "Ice Eyes", responsible for 80 murders. However, he is betrayed while planning the mob's most daring hit.

Lizzi Marriott, 19, goes missing, and Kat McDonough admits she offered her to her abusive boyfriend, Seth Mazzaglia, who killed her.

A respected English doctor is suspected of killing elderly patients, and when a will is contested, the truth reveals him as Britain's most prolific killer.

In America's first mass shooting, a sniper opens fire from the University of Texas clock tower. As the body count rises, two cops and a civilian make a daring climb to stop him.

Young, female students have disappeared with alarming frequency from the college town of Santa Cruz, California. Mutilated body parts show up as a human jigsaw puzzle.

A man kills seven in a Honolulu office, and police find a disturbed suspect haunted by his mother's ghost and paranoid of his co-workers.

Patients in New Jersey and Pennsylvania die mysteriously, leading to a meek man seeking control over life and death.

A fisherman finds a woman's body in Missouri, leading police to Richard Davis, whose camcorder reveals footage of assaults and murders of missing women.

A man in a Santa suit kills at a Christmas party in Covina, California, then flees with cash and a plane ticket, revealing a shocking motive.