The Department

Deputy Chief John Mahoney - Investigative Services Division

DC Mahoney

Deputy Chief John J. Mahoney III is the Commander of the Investigative Services Division and is a former Deputy Chief of Patrol Operations. He was appointed to the MBTA Transit Police Department in 1983.

In March 2011 the Anti-Corruption Unit under his command uncovered what has become the largest fare evasion scheme in the history of the MBTA to manufacture and sell millions of dollars worth of valid but unauthorized MBTA passes.

As Division Commander, he oversees the Criminal Investigation Unit, the Anti-Corruption Unit, Crime Scene Services and Juvenile Services. He has served in the Investigative Services Division for nineteen years. Prior to his promotion to Deputy Chief, he served in various supervisory positions including Sergeant Detective and Commander of the Anti-Corruption Unit, Sergeant Detective and Commander of the Major Case Unit, Sergeant Detective Supervisor of Criminal Investigations and Crime Scene Services, Director of Security for the MBTA Revenue Collection Facility, Patrol Sergeant as a shift Commander and Street Supervisor. As a Detective, he was assigned to the Criminal Investigation Unit and Anti-Crime Unit and US Drug Enforcement Administrative Interdiction Task Force Transportation Group 19.

He also served in the Patrol Operations Division in foot and Mobile Patrol.