Born in Breaux Bridge, Louisiana, Melanson was known as a drifter and con artist, spending much of his life behind bars. His early crimes included burglaries and sexual assaults in Orange and Jefferson County, Texas. For these offenses, he was sentenced to 12 years but served only half that time. While incarcerated in Texas, he was reportedly involved in the death of a fellow inmate. In 1975, he faced extradition for a rape trial, resulting in a life sentence. This sentence was later reduced, leading to his release in March 1988, just months before the suspected murder of a victim.

Anita Andrews, a former county fair beauty queen, was a 51-year-old single mother juggling two jobs. She worked at Napa State Hospital and also helped run the family bar, Fagiani's Cocktail Lounge, which she and her sister Muriel inherited from their father. On July 10, 1974, Anita was last seen alive tending to the bar near closing time with a stranger lingering around.

The next morning, Muriel discovered Anita's body in a pool of blood. She had been raped, her clothes torn, stabbed 13 times with a screwdriver, and her throat slashed. Her Cadillac Eldorado was also missing. Several clues were left behind, including a cigarette butt, a partial bloody fingerprint on a staircase, and fingerprints on a bottle and an open cash register. Despite these clues, it took decades to solve her case.

In August 1974, Melanson arrived in Gunnison County, Colorado, claiming to be an experienced sheepherder. He was hired by a local rancher to hunt mountain lions and coyotes. One afternoon, he met ranch hand Charles Matthews at the Timbers Bar in Gunnison and asked for a ride. When Matthews' car broke down, Michele Wallace, returning from a backpacking trip, offered them a lift. After dropping off Matthews, Michele and Melanson continued on, but she was never seen alive again.

Wallace's disappearance became a cold case until a county sheriff reopened it in the early 1990s. Her remains were eventually found off a remote mountain road, but the exact cause of her death couldn't be determined.

Pauline Klumpp, 51, was renting a home to Melanson, his ex-wife, and her new boyfriend in Port Acres, Texas. In 1988, she asked Melanson for help with her air conditioner and to pick up a TV. After that, she mysteriously vanished. Her husband, who was working out of town, returned home to find a pot of gumbo that had been cooking for days. Four days later, her car was found behind a grocery store with the TV still inside. Detective Scott Gaspard, investigating Klumpp's cold case, identified Melanson as the prime suspect from the beginning.

In August 1988, Melanson was in Walker, Louisiana. He met 24-year-old Charlotte Sauerwin at a laundromat and posed as a land developer. When others left, Melanson attacked, raped, and tortured Charlotte before strangling her and slashing her throat. He then disposed of her body near a shed.

In January 1992, Melanson was arrested in Kentucky on unrelated burglary charges. After Michele Wallace's remains were found, he was extradited to Colorado and convicted of her murder in 1993, receiving a life sentence based on hair evidence. In 2000, new federal DNA laws linked him to the murders of Andrews and Sauerwin. He was convicted of Andrews' murder in 2011 and given another life sentence. Melanson repeatedly sought parole without success and died in prison on May 22, 2020. His death was announced in 2021 when the Napa District Attorney's Office checked on his status.