Rupert Sookman was born on February 25, 1945, in Trinidad and Tobago. He was one of seven children, and his parents were Indo-Trinidadian and Tobagonian. Not much is known about his early life. After high school, he became a teacher for both elementary and high school students.

Rupert and his family later moved to Denver, Colorado, to escape discrimination from the majority ethnic African population in Trinidad and Tobago. After moving to Denver, he joined the United States Army and fought in the Vietnam War. He was honorably discharged and returned to Denver, where he opened a clothing store.

Rupert re-enlisted in the Army but left again because he had trouble adjusting and his business had failed, leaving him without an income. He then moved to Los Angeles, California, and changed his name to Michael Herbert Singh. The exact date or reason for the name change is not clear.

In 1975, Singh started dating 16-year-old Candace Lynn Starr. However, he soon turned violent, and Starr ended the relationship. Upset by this, Singh kidnapped her at gunpoint from her home in Los Angeles on September 21, while her two younger sisters watched in fear. He kept her hostage for several days and eventually took her to a convenience store in Gallup, New Mexico. There, he shot and killed her.

After the murder, Singh fled in his van. Witnesses saw part of his face and noted the van's color. This information was given to the police, but they couldn't gather more evidence or identify the victim. The case went cold for decades. In November 2009, Starr was identified through DNA submitted to CODIS, matching her profile on The Doe Network.

After Starr's murder, Singh moved to Springfield, Missouri, and married Mary Ann Spain, a 29-year-old divorcée with two children. Like before, Singh became violent, leading to frequent arguments. On September 23, 1976, during a heated argument, Singh shot Mary in front of her house and fled. Her 5-year-old daughter alerted the neighbors, who called the police. An autopsy revealed Mary was shot once in the chin and three times in the chest and left arm.

Singh was arrested the same day along Route 63. In his car, police found a pistol. He claimed to be an unemployed construction worker and listed his wife's home as his address. He was extradited back to Missouri, held on second-degree murder charges, and a $75,000 bail. Singh requested a vegetarian diet in prison, which was granted by the court.

Singh's trial was set for March 1977 but was delayed due to a violent outburst during a hearing. He was restrained by seven bailiffs, and the judge ordered another evaluation. Psychiatrists deemed Singh sane, and his trial was rescheduled for August 1.

In July, Singh tried to disqualify Judge James H. Keet, alleging prejudice, but Keet refused. Singh then claimed a physical ailment to delay the trial, but this was denied. During the trial, Mary's children testified about the murder. A forensic pathologist explained the fatal gunshot wounds. Singh claimed Mary was the aggressive one and that her death was accidental. He alleged she was a closeted bisexual who forced him into relationships with men. These claims were denied by family members and witnesses.

Singh was found guilty of manslaughter with a 12-1 jury decision. After a failed bid for a new trial, he was sentenced to 10 years in prison. In 1980, a court ruled he was eligible for half of his wife's $9,500 life insurance policy since manslaughter wasn't considered intentional murder.

After serving four years, Singh was moved to the Missouri Department of Corrections Honor Center in Kansas City. He married Susan Irving but soon became violent. On May 13, 1982, he was charged with assault after Susan reported he kicked her in the face and ribs. His court appearance was set for June 3, but he fled while on work release.

On May 25, he abducted Susan from her home in Kansas City, took her to a rural area near Camden Point, and bludgeoned her to death. While attempting to bury her body, Singh was caught by officers responding to a trespassing complaint. He tried to escape but was arrested after a short chase. Singh was scheduled for a preliminary hearing on June 11. On July 4, he tried to escape prison but was thwarted by another inmate.

Singh's murder trial was set for July 16, 1984. Despite some psychiatrists claiming he was "grossly disturbed," he was found not guilty by reason of insanity and transferred to the Fulton Medical Clinic. On March 30, 2005, Singh was stabbed to death by fellow inmate Rahaman M. Muhammad, who wanted to be placed back into police custody and decided to kill someone.

Four years after his death, Singh was identified as the murderer of Candace Starr through DNA evidence. Starr's sister, Pamela Mulligan, said she was glad her sister's murder was finally resolved and felt justice had been served.