by Jenny Morrill

Jack the Ripper was responsible for Britain's most notorious wave of unsolved murders. Between August and November 1888, he left a trail of victims in his wake, reducing London to a state of terror. Yet despite leaving taunting clues, and even sending handwritten notes to the police, Jack the Ripper was never caught. The police working on the case identified well over a hundred potential suspects, but were unable to narrow it down any further. Modern research still hasn't solved the case, but theories have emerged as to the killer's identity. Here are five candidates.

1. THOMAS NEILL CREAM

Photographs of Cream and materials from the London Metropolitan Police. Image credit: Wellcome Images // CC BY 4.0

Dr. Thomas Neill Cream was known as “The Lambeth Poisoner” after killing a number of prostitutes with strychnine during the 1890s. He was sentenced to be hanged for these poisonings, and as his sentence was being carried out, he is said to have told the executioner “I am Jack the ...” just before the trap in the gallows opened. The fact that he was imprisoned in Chicago during the Ripper murders pours some cold water on the theory—unless, as some think, he had a double who served the time for him.

2. JILL THE RIPPER

After the murder of Mary Jane Kelly in November 1888, a seemingly credible witness described seeing her in the early morning hours, long after doctors believed she had died. This led one detective on the case to theorize that perhaps the killer dressed as a woman—or was a woman. The detective, Inspector Abberline, eventually came up with the idea that the killer was likely a midwife, someone would have had the anatomical knowledge necessary to kill in the Ripper’s uniquely gruesome way. A midwife would also have had easy access to women’s homes, and wouldn’t have been given a second glance for blood-stained clothing. In 1939, an author named William Stewart wrote Jack the Ripper: A New Theory, postulating that the killer was a female abortionist who had been betrayed by another woman and gone insane while in prison.

3. SIR JOHN WILLIAMS

Sir John Williams is one of the more high-profile suspects, having worked as the royal obstetrician. Although he wasn't thought to be a suspect at the time, a 2005 book, Uncle Jack, written by a descendent, names him as the Ripper. The book goes on to claim that the women were murdered and mutilated as a way to research the causes of infertility. However, many scholars claim the book's theories—based primarily on a knife in Williams’s collection, some slides of “animal matter,” and his proximity to the site of the murders in November 1888—leave much to be desired.

4. JOHN PIZER

The evidence against bootmaker John Pizer appears to have been circumstantial. For some time, the police and the press had been searching for someone they named “Leather Apron,” based on testimony from some 50 prostitutes who claimed the same man had mistreated them. According to the testimonies, he always carried a knife and wore a leather apron, traits that coincided with Pizer's trade. At least one local sergeant also believed that Pizer went by the nickname “Leather Apron.”

Pizer was cleared by the police of being Jack the Ripper when Mary Ann Nichols was murdered in September 1888. He was able to provide a full account of his whereabouts, one which was backed up by many others, including the police.

5. SIR WILLIAM GULL

Two things make Sir William Gull, a physician to Queen Victoria, one of the most well-known suspects. The first is an account presented in late 19th-century newspaper stories and Stephen Knight's 1978 book, Jack the Ripper: The Final Solution of a medium named Robert James Lees, who supposedly used his psychic powers to establish that Gull was the murderer.

The second is the 2001 movie From Hell, adapted from the Alan Moore graphic novel of the same name and based on a letter sent to the police (along with a kidney preserved in wine) from an anonymous source at the time of the murders. Although the film implicates Sir William Gull, modern scholars believe the letter implicates several potential culprits, so the guilt of William Gull remains unproven.