As an assistant district attorney in Brooklyn in 1940, Turkus interrogated mobster Abe Reles, who had been arrested for murder. Reles became a government informant who revealed the existence of a violent gang of racketeers in the Brownsville section of Brooklyn. The group was named "Murder Inc." by the press.
Reles's revelations led to numerous other prosecutions. Turkus later wrote a book about Murder Inc., and in the early 1950s became host of the TV series Mr. Arsenic.