Jack Callahan

Jack Callahan (died 1990) was a criminal that worked undercover for the police in order to dismantle the Warriors of Freedom.

Early life
At some point in 1980, Jack secretly worked with Garfield in order to bring down the Warriors of Freedom gang in exchange for immunity.

Angel's vengeance and death
In 1990, Jefferson Zacharias' daughter Angel Zacharias started a crusade against those that were responsible for her father's death. He supplied her with explosives so that she could murder her targets. The Flash came to visit him and asked question after taking down two of his guys. Jack told the Flash that he should kill him, but he ran away after destroying his gun smuggler operation. Angel came to visit him after failing to kill Garfield. She quickly figured out that Jack was the traitor that caused the downfall of the Warriors of Freedom, and she eventually shot him. She would put a necklace with the last piece of the Warriors of Freedom medallion on him. Later, when the Flash arrived, Jack with his dying breath had the time to tell the Flash his killer's name "Angel"