Masked gunmen burst into a Belfast pub and shot to death a leader of the largest Protestant paramilitary group in Northern Ireland, police said. A second man was shot to death and five others were wounded in the attack. Police identified one of the dead as Jimmy Craig, a senior official in the Ulster Defense Assn. Police said the gunmen ordered customers in east Belfast’s Castle Inn to lie on the floor, then opened fire. No one claimed responsibility for the attack, but suspicion fell on the Irish Republican Army, which is fighting to end British rule in Northern Ireland. In the early 1970s, Craig was charged with the murder of Maire Drumm, president of Sinn Fein, the legal political wing of the IRA, but he was acquitted.