Complex sentence: In 1936, Tolson joined Hoover to arrest bank robber Alvin Karpis; later that year, Tolson was in a gunfight with New York City gangster Harry Brunette, and, in 1942, participated in capturing Nazi saboteurs on Long Island and Florida.
Split into simpler sentences: In 1936, Tolson joined Hoover to arrest bank robber Alvin Karpis; later that year, Tolson was in a gunfight with gangster Harry Brunette. In 1942, Tolson participated in capturing Nazi saboteurs on Long Island and Florida.