Robert Mark Edwards was born on June 14, 1961, in Long Beach, California. Details about his early life remain limited, but records indicate a history of criminal behavior, including burglary, theft, auto theft, and drug offenses. He used multiple aliases and Social Security numbers, suggesting a pattern of deception and evasion. Edwards' criminal activities spanned several states, and he had a history of violating parole conditions. 

On May 15, 1986, 55-year-old realtor Marjorie Elaine Deeble was found dead in her Los Alamitos, California, apartment. Deeble, the mother of Edwards' then-girlfriend, was discovered face-down, with her hands bound and a belt around her neck, which was tied to a dresser drawer, suspending her neck above the floor. She had been sexually assaulted, and a mousse can was found at the scene, indicating further sexual mutilation. Despite being questioned, Edwards was not charged at the time due to insufficient evidence.

On January 25, 1993, 67-year-old realtor Muriel E. Delbecq was murdered in her condominium in Kihei, Maui, Hawaii. Edwards broke into her residence, bound her, and proceeded to beat and strangle her. He sexually assaulted her, inserted a mousse can into her vagina, shaved her pubic hair, and mutilated her body. He stole personal items, including her wedding ring and clothing. Delbecq's body was discovered the next day, and forensic evidence, including Edwards' fingerprints and DNA, linked him to the crime.

Edwards was arrested on February 2, 1993, in connection with Delbecq's murder. During the investigation, similarities between the two murders emerged, leading to his extradition to California after his conviction in Hawaii. In Hawaii, he was convicted on March 11, 1994, and sentenced to five consecutive life terms. In California, his first trial in 1996 resulted in a hung jury regarding the death penalty. A retrial in 1998 led to a unanimous death sentence on September 9, 1998. Edwards remains on death row at San Quentin State Prison.