Due to the unidentified nature of Bible John, details about his life before the murders remain unknown.

Between 1968 and 1969, three women in Glasgow, Scotland—Patricia Docker, Jemima MacDonald, and Helen Puttock—were murdered after attending the Barrowland Ballroom. Each victim was beaten and strangled, with their handbags missing from the crime scenes. Notably, all three were menstruating at the time of their deaths, leading investigators to suspect a sexual or ritualistic motive. The moniker "Bible John" originated from the final victim's sister, who reported that the suspect had quoted Bible verses and expressed disdain for adultery during their taxi ride together.

Despite extensive investigations, Bible John was never identified. In the late 2000s, convicted serial killer Peter Tobin was considered a potential suspect due to similarities in modus operandi and his presence in Glasgow during the late 1960s. However, DNA testing and further inquiries eventually eliminated Tobin as a suspect. In 2023, a BBC podcast titled "Bible John: Creation of a Serial Killer" prompted renewed interest in the case, leading Police Scotland to review the investigation. The podcast alleged that police at the time may have covered up the identity of Bible John, suggesting he was John Irvine McInnes, the cousin of a senior police officer.

As of 2025, the true identity of Bible John remains unknown, and the case is considered one of Scotland's most notorious unsolved serial murder investigations.​