Kevin Cooper was born Richard Goodman on January 8, 1958, near Pittsburgh, Pennsylvania. His early life was troubled. When he was just two months old, his mother placed him in an orphanage. He was adopted at the age of six months by Melvin and Esther Cooper, who renamed him Kevin Cooper.

As a child, Kevin faced significant challenges. He was subjected to physical abuse from his adoptive parents. This difficult home life led him to run away from home many times. As he grew older, his behavior did not improve. During his teenage years, he frequently found himself in trouble with the law. He was sent to juvenile custody multiple times.

On the morning of June 5, 1983, Bill Hughes went to pick up his son Christopher from a house in Chino Hills, California. When he entered the home, he found Christopher's friends, Douglas and Peggy Ryen, their 10-year-old daughter Jessica, and his own son dead. They had been attacked with multiple weapons, and only 8-year-old Josh Ryen survived, although he had severe injuries. Resources in the home suggested no robbery had taken place, as Mrs. Ryen's purse was not taken.

The San Bernardino County Sheriff's deputies quickly identified Kevin Cooper as the primary suspect. Cooper had admitted to hiding in a vacant house nearby for two days before the murders and made phone calls to friends asking for money to flee the area. Cooper claimed that he left the house on the night of the murders and hitchhiked to Mexico, where he checked into a hotel in Tijuana on the afternoon of June 5.

Cooper later got involved in another incident while staying on a boat owned by a couple, where he was accused of raping a woman. When the victim went to report the crime, she recognized Cooper from a wanted poster and he was apprehended as he tried to swim away.

Evidence collected linked Cooper to the crime scene. A button matching prison-issued clothing was found in the house where he slept, along with a blood-stained rope that resembled one from the Ryen's property. Additional forensic tests indicated the presence of blood in places within the house he used. Cooper's hair and cigarette butts, which contained his DNA, were found in the Ryen family’s vehicle.

At trial, Cooper admitted to his escape from prison but denied any involvement in the murders. He claimed he left the house and stole a purse before heading to Mexico. The sole survivor, Josh Ryen, had made various statements regarding the attack, initially suggesting multiple attackers, but later indicated a single assailant.

A jury found Cooper guilty of four counts of first-degree murder and one count of attempted murder, leading to a death penalty sentence.

In subsequent years, questions arose about the legitimacy of the evidence against Cooper. Allegations were made regarding possible tampering, mishandling of evidence, and a lack of adequate defense in his trial. Over time, there have been multiple appeals for his conviction to be reviewed, along with calls for new DNA testing to reevaluate the evidence. Despite the controversies, the courts have maintained the conviction, although discussions about Cooper's potential innocence continue in various legal and media forums.