After a deranged shooter killed her husband and wounded her son on a Long Island commuter train in 1993, she went to Congress on a mission to curb gun violence.

Gun control crusader and former U.S. Rep. Carolyn McCarthy of New York has died. She was 81. McCarthy was a political novice who successfully ran for Congress in 1996 as a crusader for gun control after a mass shooting on a New York commuter train left her husband dead and her son severely wounded.

Ms. McCarthy’s political career began with tragedy in December 1993, when her husband was among six people killed in a shooting on a Long Island commuter train.