Marvin Charles Gabrion was born on October 18, 1953, in the United States. He was the fifth of six children in his family. His parents were Marvin Sr. and Elaine Gabrion. Marvin Sr. struggled with alcoholism. It was reported that he abused his wife and children. Because of this, Gabrion's parents were often not at home. This left Gabrion's older sisters to take care of him and his brothers.

Growing up, Gabrion's childhood was filled with difficulties. The situation at home was chaotic. His sister Yvonne remembered a time when their mother threw a butcher knife at their father during an argument. 

On August 7, 1996, Rachel Timmerman reported to the Newaygo County Sheriff's department that Marvin Gabrion had raped her. The previous evening, she had been invited to a card game. During the car ride, Gabrion forced the other passengers out and drove off with Rachel. He was arrested and charged with the crime.

On June 3, 1997, just two days before Gabrion's trial, Rachel left her home with her 11-month-old daughter, Shannon. She told her family she was going on a date. Shortly after, her family received letters in her handwriting claiming that the rape allegations were false and stating that she planned to leave town with a man she referred to as "Delbert." Her disappearance was not investigated right away.

On July 5, 1997, Rachel's body was discovered in Oxford Lake, chained to cinder blocks and with duct tape on her face. The coroner concluded she was alive when she entered the water and died from drowning. Gabrion became a prime suspect in her murder. The investigation revealed that keys matching the padlock on Rachel's body were found at Gabrion's home, along with concrete blocks that matched those used to weigh down her body.

Mikey Gabrion, Marvin's nephew, helped lead police to a campsite often used by Marvin. There, they found evidence including bolt cutters, chains, and duct tape. Rachel’s daughter, Shannon, has never been found, but it is believed Marvin was responsible for her death as well.

Marvin Gabrion was also suspected in several other disappearances. He lived in a home owned by Robert Allen, who went missing in 1995. Gabrion cashed Allen's Social Security checks and continued living in his house until 1997. Wayne Davis, the man who invited Rachel to the card game, went missing in February 1997. He was set to testify against Gabrion. Later, his body was found in Twinwood Lake, where Rachel's body was located. John Weeks, another acquaintance, also disappeared in 1997, and Gabrion was the last known person to see him.

In 2002, Gabrion was tried for Rachel Timmerman's murder. Witnesses testified about Gabrion's violent behavior and other criminal activities. The judge denied Gabrion's requests to represent himself in court due to his misconduct during the trial. He was convicted and sentenced to death.

Gabrion’s case is notable because it was tried in federal court, allowing the death penalty to be sought. Michigan has not permitted capital punishment since 1846, but because Rachel's murder occurred on federal land, the federal government was allowed to pursue the death penalty. He became the first person to receive this sentence in a non-death penalty state after the federal death penalty was reinstated.

In 2011, Gabrion appealed his conviction, but while the conviction was upheld, his death sentence was initially overturned. However, in 2013, the death penalty was reinstated. Gabrion is currently incarcerated at the United States Medical Center for Federal Prisoners in Springfield, Missouri. Gabrion was among 37 individuals whose death sentences were commuted to life imprisonment by President Joe Biden on December 23, 2024.