Anthony John Allen was born as Anthony John Angel on June 11, 1934, in Torbay, England. He grew up in Bournemouth, a town on the southern coast of England. Little is known about his childhood, but it is clear that he had some difficulties as a young adult. In the 1950s, he married a woman named Monica.

In 1966, Allen was caught stealing money from his workplace. To avoid being punished for this crime, he decided to fake his own death in 1967. He chose a location known for its association with suicides, Beachy Head, and left behind a pile of clothes along with a suicide note. After this event, he adopted a new identity. Shortly after, he met and married a woman named Patricia, though this marriage was illegal at the time.

In July 1968, he was caught for bigamy and other offenses, which led to a suspended prison sentence. His legal troubles continued in 1970 when he was convicted for burning three bags of mail he had not delivered. This crime resulted in him spending a year in jail.

Eventually, Allen divorced his first wife, Monica, and he married Patricia legally in 1972. By May 1975, he and Patricia had two children together, a son named Jonathan, who was seven years old, and a daughter named Victoria, who was five.

In May 1975, Anthony John Allen was living with his wife Patricia and their two children, Jonathan, aged 7, and Victoria, aged 5, in Salcombe, Devon. During the last days of May, Allen reported a conflict with his wife. He claimed that after they argued, she left home and returned two days later with the children. However, he did not report them missing. None of them were seen again.

Later, police found Patricia's car nearby. Inside the car were dinghy oars, which raised further questions. Initially, the investigation did not yield enough evidence for a prosecution. Years later, Eunice Yabsley, who had a relationship with Allen, published a book in 1992 about their experiences and the unresolved disappearance of his family. In her book, she noted that Allen had scratches on his arms around the time Patricia and the children went missing.

The case remained cold until 2001, when police reopened the murder investigation. They discovered that the person Allen had claimed was Patricia's boyfriend had suffered a severe stroke years before and could not have helped her as Allen had suggested.

In 2002, Allen was tried and found guilty of murdering his wife and two children, despite the fact that their bodies were never found. He was sentenced to life in prison. He died on August 8, 2015, while still claiming he was innocent of the crimes.