DUBLIN, Ireland - The start of the IRA-allied Sinn Fein's annual conference Friday was overshadowed by the party's efforts to contain a political firestorm surrounding the killing of a Catholic man by members of the outlawed militant group The five sisters of Robert McCartney, who was stabbed to death by an IRA gang in Belfast, have spent five weeks demanding the Irish Republican Army lift an apparent death threat against dozens of witnesses to the Jan. 30 attack. Sinn Fein, which initially criticized police efforts to find the killers, has suspended seven party members allegedly involved in the killing and...