Joseph Barnett, also known by his nicknames Danny Barnett and “Joe”, was a fish porter who worked at Billingsgate Market in the 19th century, located in the East End of London, and later became known for being the roommate of Mary Jane Kelly. It was not suspected that he had murdered her and, even less, that he was Jack the Ripper, until recently, when he was proposed on the basis of speculation and circumstantial evidence.