Questions raised about decision to not charge retired jail guard in New York subway slaying

In this undated photo provided by Elizabeth Arroyo, construction worker Gilterto Drogheo sits with his young daughter, Gia, in New York. On March 10, 2010, Drogheo was shot and killed in New York by William Groomes, a 69-year-old retired jail guard licensed to carry a concealed weapon. Groomes claimed he was trying to arrest Drogheo for assault. (Gilterto Drogheo/Elizabeth Arroyo via AP) (The Associated Press)

The killing of an unarmed man in a New York City subway station by a retired city jail guard has devastated the man's family and raised questions about the line separating self-defense from vigilantism.

William Groomes shot Gilbert Drogheo in March. Cellphone video shows Groomes appearing to pursue Drogheo through the station before they struggled and a gunshot went off. Groomes is licensed to carry a gun.

Both sides agree there were angry words and a fight, but there are conflicting accounts about who was the instigator.

But prosecutors found there wasn't enough evidence to charge Groomes. They concluded Drogheo was the aggressor and Groomes had a right to defend himself.

The decision has outraged Drogheo's family members, who want the case reopened and put before a grand jury.