American attorney mostly known for his investigations into Communist activity in the United States 1950-1956.
Cohn gained special prominence during the Army–McCarthy hearings. He was also a member of the U.S. Department of Justice's prosecution team at the espionage trial of Julius and Ethel Rosenberg.
Cohn helped to secure convictions in a number of well-publicized trials of accused Soviet operatives.
Cohn was a homosexual and died as the result of AIDS.