Organized Crime

Behind the scenes, prosecutors' in-house investigators key to prominent NY criminal probes

  • In this June 9, 2015 photo, Joe Ponzi, former chief of the Brooklyn District Attorney Investigators, poses in front of Brooklyn's Borough Hall in New York. In his 36 years on the job, Ponzi oversaw some of the borough’s most famed cases, including the indictment of two sitting state supreme court judges. A famed polygraph expert, Ponzi is credited with gaining the confession of a conspirator who proved key in the prosecutions against the so-called Mafia Cops. (AP Photo/Kathy Willens)

    In this June 9, 2015 photo, Joe Ponzi, former chief of the Brooklyn District Attorney Investigators, poses in front of Brooklyn's Borough Hall in New York. In his 36 years on the job, Ponzi oversaw some of the borough’s most famed cases, including the indictment of two sitting state supreme court judges. A famed polygraph expert, Ponzi is credited with gaining the confession of a conspirator who proved key in the prosecutions against the so-called Mafia Cops. (AP Photo/Kathy Willens)  (The Associated Press)

  • In this June 9, 2015 photo, Joe Ponzi, former chief of the Brooklyn District Attorney Investigators, poses in front of Brooklyn's Borough Hall in New York. In his 36 years on the job, Ponzi oversaw some of the borough’s most famed cases, including the indictment of two sitting state supreme court judges. A famed polygraph expert, Ponzi is credited with gaining the confession of a conspirator who proved key in the prosecutions against the so-called Mafia Cops. (AP Photo/Kathy Willens)

    In this June 9, 2015 photo, Joe Ponzi, former chief of the Brooklyn District Attorney Investigators, poses in front of Brooklyn's Borough Hall in New York. In his 36 years on the job, Ponzi oversaw some of the borough’s most famed cases, including the indictment of two sitting state supreme court judges. A famed polygraph expert, Ponzi is credited with gaining the confession of a conspirator who proved key in the prosecutions against the so-called Mafia Cops. (AP Photo/Kathy Willens)  (The Associated Press)

Public corruption cases making headlines across New York are old news to a little-known group of lawmen who work in state and federal prosecutors' office.

Career investigators have been behind some of the most notorious investigations in New York City history — though they're largely unknown outside law enforcement circles.

State district attorney investigators called DIs can trace their roots back to the 1930s-era racket busters under the famous DA Thomas E. Dewey.

And former Manhattan District Attorney Robert Morgenthau said he hired criminal investigators during his stint as a U.S. attorney in the 1960s to take on such cases.

City DIs have played key roles in probes into bank money laundering, Albany lawmakers' corruption, decades-old wrongful conviction cases and Mafia prosecutions.