When Bruce Blackwood, 55 and from Queens, New York, called out of work and said he fell in the shower, then seemingly vanished, his family and police knew something was wrong.
After Jonathan Crupi called 911 to say he arrived home to find his wife dead, authorities discovered that Simeonette Mapes-Crupi had been pushed down a flight of stairs and stabbed 15 times.
After the "mangled" body of Rachel Siani, 21, was found in New Jersey after being thrown from a bridge, police tracked down a patron at the Pennsylvania club she worked at.
Shannon Schieber, a 23-year-old Wharton School doctoral student, was found raped and strangled to death in her Philadelphia apartment. Her attacker was then linked to multiple crimes in two states.
The body of Alice Hufnagle, 67, was found in an upstairs bedroom of her suburban Philadelphia home, and a blood-stained Scream mask was among clues found at the killer's home.
Rhonda Smith, 42, was found face down and shot twice in a church office in Springfield Township when a close friend stumbled upon the horrifying scene.
Rosie Juarez, the eldest niece of serial killer Richard Ramirez, says her uncle started abusing her when she was just 6. It continued for years, she said.
Alberto Martino, 54, was found lying in a pool of blood outside the radio station where he was a disc jockey after wrapping his show. He had "serious wounds around the head."
Authorities discovered a "horrendous scene" after rushing to the Bensalem, Pennsylvania apartment of Christian Rojas, whose friend found him dead in a bathtub.
After the lifeless body of Elaine Goldberg, 21, was found in a vacant lot in the Kensington neighborhood of Philadelphia, two other women were found dead in similar, brutal fashions.
Dr. James Sowa, a 64-year-old chiropractor, was found bleeding and unconscious in his home. Investigators traced the crime to a suspect who was angry at him for a shocking reason.
Surveillance video showed someone firing a gun at the back of Patricia McDermott's head. When Juan Covington emerged as a suspect, police were shocked by what came next.