On December 5, 1873, Bridget Landregan is found beaten and strangled to death in the Boston suburb of Dorchester. According to witnesses, a man in black clothes and a flowing cape attempted to sexually assault the dead girl before running away. In 1874, a man fitting the same description clubbed another young girl, Mary Sullivan, to death. His third victim, Mary Tynan, was bludgeoned in her bed in 1875. Although she survived for a year after the severe attack, she was never able to identify her attacker.
Residents of Boston were shocked to learn that the killer had been among them all along. Thomas Piper, the sexton at the Warren Avenue Baptist Church, was known for his flowing black cape, but because he was friendly with the parishioners, nobody suspected his involvement. But when five-year-old Mabel Young, who was last seen with the sexton, was found dead in the church's belfry in the summer of 1876, Piper became the prime suspect. Young's skull had been crushed with a wooden club. Piper, who was dubbed "The Boston Belfry Murderer," confessed to the four killings after his arrest. He was convicted and sentenced to death, and he was hanged in 1876.