Complex sentence: Ahearn arrested Fratianno, who, at this point, was looking at life in prison or death by Brooklier's order, agreed to become a government witness against the Mafia.
Split into simpler sentences: Ahearn arrested Fratianno, who, at this point, was looking at life in prison or death by Brooklier's order. Fratianno agreed to become a government witness against the Mafia.