Seamus Twomey, 70, a founder of the modern Irish Republican Army and the mastermind of the IRA's deadly car-bomb campaign in Belfast. Twomey, former manager of a bookmaker's shop, was a founding member of the breakaway Provisional IRA, set up after trouble flared in Northern Ireland in 1969. Twice the IRA's chief of staff, he was arrested in the Irish Republic in 1973 but escaped with two other IRA leaders in a dramatic helicopter airlift from Dublin's Mountjoy Prison in 1973. He was recaptured in a Dublin car chase a month later. As head of the guerrilla group's Belfast Battalion in 1972, he had flown to London for controversial cease-fire talks with the British government. But the lull was short-lived. On July 7, 1972, the IRA detonated 22 bombs across Belfast that killed nine people. It became known as "Bloody Friday," one of the bloodiest days in the 20-year-long IRA campaign to oust Britain from the north. Twomey was arrested the following year. He was released from prison in 1982. Sept. 12 of a heart condition in a Dublin hospital.