William Scott Day was born on October 21, 1951, on an American military installation in Japan. He exhibited high intelligence from an early age, with a strong interest in literature. After his father's death during his teenage years, Day moved to Michigan and enlisted in the Marine Corps. However, he deserted his post and was later arrested for attempting to rape and kidnap a woman, leading to a seven-year prison sentence. Throughout the late 1970s and early 1980s, Day faced multiple arrests for offenses including heroin possession, theft, and kidnapping. He also escaped from prison on several occasions. In 1982, after escaping from a prison camp in Caro, Michigan, he kidnapped and robbed an 80-year-old woman, resulting in an additional seven-year sentence. Due to his depression, Day was transferred to the Center for Forensic Psychiatry in Ypsilanti, Michigan, where he was considered a model patient and befriended security worker Thomas Frederick Fortunato.

On December 4, 1986, with assistance from Fortunato, Day escaped from the psychiatric facility by hiding in a laundry cart. They traveled to Louisville, Kentucky, where Day eventually abandoned Fortunato. Day then embarked on a 39-day crime spree across multiple states:​

• December 9, 1986 – Nashville, Tennessee: Day murdered 74-year-old Mary Catherine Strobel by stabbing and strangulation.
• December 1986 – Tucson, Arizona: He beat and robbed 76-year-old Roberto Arzapalo-Alcoser, who later died from his injuries
• January 2, 1987 – Marianna, Florida: Day killed 55-year-old pawn shop clerk Evan Johnson and stole valuables from the store. ​
• January 6, 1987 – Fort Stockton, Texas: He murdered Billie Taylor by beating and stabbing her, leaving her body by the roadside. ​
• January 7, 1987 – New Orleans, Louisiana: Day stabbed 27-year-old Andrew McClelland multiple times in a hotel room and stole his car.
• January 12, 1987 – Van Horn, Texas: He killed 53-year-old Stanley Robertson, stole his car, and was later apprehended after the vehicle's tire blew out.

Upon arrest, Day confessed to the murders. He was extradited to Tennessee, where he was convicted for the murder of Mary Catherine Strobel and sentenced to three consecutive life terms without parole. Day died of natural causes in prison on February 4, 2006.