Harry Vallon was a New York City gambler and mob informant. He turned state's evidence and testified against the gunman in the murder of Herman Rosenthal, and also against Charles Becker, under a promise of immunity from the district attorney. He testified as one of four mob informants, along with Bridgey Webber, Jack Rose, and Sam Schepps at the Becker-Rosenthal trial. Based upon his testimony, Charles Becker, along with the four gunmaen involved in the murder, were convicted and sentenced to death. In 1936 he was threatened with rearrest in the case.
- "People v. Becker". Northeastern Reporter. 1915.
- "Becker Informers Now Ready To Flit. Schepps West for Vaudeville, Webber to Europe, Rose and Vallon Won't Tell". New York Times. November 21, 1912. Retrieved 2010-12-10.
- "Harry Vallon Released. "Bridgie" Webber's Brother Stops Prosecution in Foreclosure Case". New York Times. December 7, 1913. Retrieved 2010-12-10.
- "Dodge Refuses to Grant Lawyer's Request in Rosenthal Case". New York Times. September 10, 1936. Retrieved 2010-12-13.