During his time in jail, his idol and brother, Charlie, was murdered by a man named George Goll.
Elmer earned his nickname "Trigger" because he would shoot people behind the ear; the police ultimately caught up with him because of his pattern hits.
Later, he murdered Edward "Poochy" Walsh who was sitting in a bar with his friend "Squeeky" on 12 July 1952.
Hunting O'Keefe, he found him in a Dorchester, Massachusetts housing project and chased him for a half an hour, firing dozens of rounds at his fleeing quarry.
Burke escaped, but was recaptured a year later while waiting for a bus in Charleston, South Carolina.
Burke was arrested after a manhunt by Major Case Squad homicide detective (1st Grade) Romolo Imundi and convicted of murdering his friend longshoreman Edward Walsh and was sentenced to death in the electric chair.