Steven David Catlin was adopted as an infant in 1944 by Glenn and Martha Catlin in Kern County, California. He dropped out of high school and exhibited a lack of interest in legitimate employment, leading to legal troubles, including arrests for forgery and credit card theft. Catlin's personal life was tumultuous, marked by multiple marriages and divorces. His fascination with automobiles led him to work with a racing pit crew, where he met his fifth wife, Glenna Kaye.

Catlin's series of murders began with his fourth wife, Joyce, who died in 1976 under suspicious circumstances initially attributed to pneumonia. In 1984, his fifth wife, Glenna Kaye, fell ill and died after a prolonged hospitalization. Later that year, his adoptive mother, Martha, also died suddenly following a brief illness. Investigations revealed that all three had been poisoned with paraquat, a toxic herbicide. 

Catlin was arrested on December 23, 1985, and charged with the murders. In 1990, he was convicted for the murders of Joyce and Martha Catlin, with the jury finding special circumstances of murder for financial gain, use of poison, and multiple murders, leading to a death sentence. He was previously convicted in 1986 for the murder of Glenna Kaye and sentenced to life imprisonment without parole.