Edward F. Costello was born in Keshcarrigan, Ireland, in the mid-1860s, and lived with his maternal grandparents after losing his father at the age of 7. In 1879, they sent him to the United States, where he lived for a time in Woonsocket, Rhode Island, working at a succession of factory jobs. He moved to Palmer, Massachusetts, in 1886, and obtained employment as a brakeman with the New London Northern Railroad; he later had an accident that cost him a leg. He married Adelaide Victoria Burns (b. 1866) on December 25, 1887, and their son, William A. Costello, was born on November 7, 1888. Costello, often drunk, grew jealous of his wife, whom he suspected of cheating on him. On June 11, 1890, after discovering that his wife was pregnant with their second child, he shot and killed William and attempted to kill Adelaide. He faced indictment in Springfield, Massachusetts, in September 1890, and his case went to trial on April 6, 1891. After his insanity plea failed, Costello was sent to the Massachusetts State Prison in Boston; he was released in the spring of 1913. Adelaide's second child, also a son named William, was born in September 1890.