Mary Sheen (aka Sweeney) was 25 and lived with Thomas Collins. Her estranged husband sometimes paid visits, creating jealousy between the two men. On 10 June, Collins was let out of prison after serving 6 months for felony. He went with Mary to his mother's home. Mary and Thomas argued, Mary accusing Thomas of an incestuous relationship with her mother. On 17th June Thomas attacked Mary with a knife causing her serious hospital treatment. She refused to press charges but 2 days later Collins attacked her again and the wounds inflicted were fatal.
Collins approached police officers and told them "I give myself up to you. I have done it." When the officers enquired as what he had done, he replied "I have murdered Mary Sheen."
Collins was known to react badly to drink, and at the time of the murder he had been drinking. Some even suspected that the allegations of incest may have been imagined. The jury found Collins guilty, leading to a mandatory death sentence. It was immediately appealed adue to evidence from some London doctors, he was reprieved and transferred to Broadmoor Criminal Lunatic Asylum.