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Walter Mack

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Walter Mack has extensive civil and criminal litigation, investigative and regulatory experience in and out of the government. From 1993-1995, he served as Deputy Police Commissioner of New York City for Internal Affairs, where he was in charge of all police investigations of police corruption and brutality and instituted new policies to combat these problems. Prior to that, Mr. Mack was an Assistant United States Attorney for the Southern District of New York, Deputy Chief of the Criminal Division, Chief of the Organized Crime Unit and Senior Litigation Counsel within that office. In that capacity he personally investigated and prosecuted at trial a number of complex and significant cases brought in the Southern District of New York. Mr. Mack served as a military police supervisor and a rifle company commander in Vietnam. He also has frequently worked with civil rights organizations, such as the Civilian Complaint Review Board in New York City, during nineteen years serving in or working with government agencies. He served as senior vice-president and associate general counsel at Shearson Lehman, where he supervised and worked with management on securities and employment matters and on compliance investigations.

Practice Areas

  • Blue and White Collar Criminal Defense
  • Securities Enforcement, Regulatory, and Broker-Dealer Matters
  • Complex Civil Litigation
  • Internal Investigations, Corporate Compliance and Monitorships
  • Criminal Defense and Appeals
  • Investigative Services


  • Columbia Law School, New York, New York
    • J.D. - 1971
    • Honors: Jerome Michael Finalist - Student Advisor
  • Harvard University, Cambridge, Massachusetts
    • B.A. - 06/1965
    • Honors: cum laude

Bar Admission

  • New York, 1973
  • U.S. District Court Southern District of New York, 1974
  • U.S. District Court Eastern District of New York, 1974
  • U.S. Court of Appeals 2nd Circuit

Representative Cases

  • U.S. v. Harold Gleason
  • U.S. v. Michele Sindona
  • U.S. v. Paul Castellano, et. al.
  • U.S. v. Anthony Gaggi, et. al.

Past Positions

  • United States Marine Corps, Captain, 1965 to 1968
  • Rogers & Well, Litigation Department, Associate, 1971 to 1974
  • Southern District of New York, Assistant United State Attorney, 1974 to 1990
  • U.S. Attorneys Office, Southern District of New York, Deputy Chief, Criminal Division, 1980 to 1981
  • Strike Force Against Organized Crime, Southern District of New York, Chief, 1981 to 1984
  • Shearson-Lehman Brothers, Associate General Counsel, 1990 to 1993
  • Internal Affairs Bureau, New York City Police Department, Deputy Commissioner of Police, 1993 to 1995
  • Shearson-Lehman Brothers, Senior Vice President, 1990 to 1993

Professional Associations

  • American Bar Association, Member
  • New York State Bar Association, Member
  • The Association of the Bar of the City of New York, Member
  • New York County Lawyers Association, Member

Current Employment Position

  • Partner