There have been over 100 suspects investigated for the Jack the Ripper murders that occurred in Whitechapel, London between 1888 and 1891.
Some are pretty unlikely - suspects include charity founder Thomas John Barnardo and Alice in Wonderland author Lewis Carroll - but there are 5 outstanding theories that are pretty difficult to ignore.
Read on and decide for yourself... who was Jack the Ripper?
1. The Vital Shawl Theory
The Suspect: Aaron Kosminski
Who? Polish barber and mental patient
Read the Book: Naming Jack the Ripper - Russell Edwards
2. From London to Chicago
The Suspect: H.H. Holmes
Who? Doctor, hotel owner and verified serial killer
Supporting Evidence: Holmes was certainly a brutal killer, but his origins are shrouded in mystery. A composite computer sketch based on previous witness testimony does seem to indicate a striking resemblance to 'America's First Serial Killer', H.H. Holmes. Is it possible that the most notorious serial killer in British history was also the dread terror of America?
Read the Book: Bloodstains - Jeff Mudgett
3. The From Hell Theory
The Suspect: Sir William Withey Gull
Who? Famed physician to the British royal family
Supporting Evidence: Gull is certainly the most popular Ripper candidate in popular culture - the theory being that a prostitute was going to bear an illegitimate heir to the throne - so authorities unleashed a madman (with medical knowledge, which Gull had) to disguise her death in a spate of killings...
Read the Book: From Hell - Alan Moore
4. The Painted Devil Theory
The Suspect: Walter Sickert
Who? British painter
Supporting Evidence: After botched surgery to correct a fistula on his penis, Sickert was unable to have intercourse. His accusers allege that this gave him great rage against women - and that his paintings reflected poses seen on the Ripper's victims.
Read the Book: Portrait of a Killer: Jack the Ripper, Case Closed - Patricia Cornwell
5. The 'Jack the Ripper was a Woman' Theory
The Suspect: Lizzie Williams
Who? Infertile wife of royal physician John Williams
Supporting Evidence: Williams was suspected of the murders, which many think she committed out of anger at her inability to bear children of her own - leading her to vent her frustrations by attacking the sexual organs of other women. Sherlock Holmes author Arthur Conan Doyle famously supported the female villain hypothesis, writing on what he called 'Jill the Ripper'.
Read the Book: Jack the Ripper: The Hand of a Woman - John Morris