On May 7, 1896, Holmes was hanged at Moyamensing Prison, also known as the Philadelphia County Prison, for four murders and six attempted murders. The murder for which Holmes would be executed for was that of his accomplice Benjamin Petzel in Philadelphia Pennsylvania [Sep 20, 1894]; evidence was also uncovered in the search for Holmes of his involvement in the subsequent murders of three of Petzel's children: Howard Petzel in Irvington, Indiana [October 10, 1894] and Alice and Nellie Petzel in Toronto, Canada [October 25, 1894] . Ironically although Holmes "Murder Castle" was undoubtedly the scene of many of his murders, it was the murder of Petzel in Philadelphia which had the clearest case for murder-as there was only very circumstansial physical evidence of the "Castle" victiums- a piece of human bone possibly from Julia Conner; remains of a child-possibly Pearl Conner; a burned gold watch chain and burned dress buttons-apparently belonging to Minnie Williams; a tuft of human female hair found in a chimney flue.