The movie "The Devil's Own" 1997

Frankie McGuire, one of the IRA's deadliest assassins, draws an American family into the crossfire of terrorism. But when he is sent to the U.S. to buy weapons, Frankie is housed with the family of Tom O'Meara, a New York cop who knows nothing about Frankie's real identity. Their surprising friendship and Tom's growing suspicions force Frankie to choose between the promise of peace and a lifetime of murder.