John Pizer, also known by the nickname Leather Apron, was a British citizen, who lived in London in 1888.

Before 1888, Pizer already had a reputation in Whitechapel for scaring prostitutes, and he had been arrested and convicted for assaulting someone with a knife.

During the panic Jack the Ripper caused with the Whitechapel murders, John Pizer was one of the suspects in the investigation performed by the Metropolitan Police Service. When this information leaked, Pizer's safety was compromised, and Inspector Frederick Abberline tasked the Assassin Evie Frye with escorting Pizer to his office for interrogation.