Is '1) Increased federal enforcement . Before Hoover's death, the FBI did not aggressively investigate the Mafia.' a logical precursor to the hypothesis 'The Mafia were not aggressively investigated before Hoover's death.'
1) Increased federal enforcement . Before Hoover's death, the FBI did not aggressively investigate the Mafia.###The Mafia were not aggressively investigated before Hoover's death.