About Us

Larry Holifield

 Larry is a co-founder and Director of Corporate Integrity Services LLC (CIS). In 2008, after his retirement from DEA  Larry joined TurnStone Investigative Group  as a Regional Director in Miami, Florida.  TurnStone is the wholly owned investigative entity of Hunton & Williams, a large international law firm.  Larry was a firm-wide resource for Hunton & Williams, managing and conducting complex domestic and international investigations involving many law firm practice areas.

Larry has 37 years of combined law enforcement experience with the St. Louis Police Department (1970-1984) and the U.S. Drug Enforcement Administration (1984-2007). 


Relevant Experience


  • Served in senior positions at the DEA, including Senior Executive Service, Regional Director for Mexico and Central America, and Deputy Special Agent in Charge of the Miami Field Division.
  • Management skills in technology utilizing state-of-art equipment available to law enforcement such as satellite tracking devices, telephone intercepts, voice recognition systems and biometrics.
  • Proficiency in directing sensitive, long term and complex domestic and international operations and investigations.
  • Experienceed in negotiations at the highest levels of policy makers among diverse cultures.
  • Wide international, professional network of local,state and federal agencies as well as Fortune 500 companies.
  • Excellent problem-solving skills capatilizing on over 12 years served in Latin America (Mexico, Guatamala and Colombia).

Don R. Zell

 Don is a co-founder and Director of CIS.  He has been involved in conducting and managing privated sector investigations since 1993.  In 2006, he became the CEO of TurnStone Investigative Group, an investigative entity wholly owned by Hunton & Williams law firm.  Before joining TurnStone, Don served in a similar capacity with another large international law firm.  In addition to the overall operations of the investigative entities, he actively conducted and managed large and complex domestic and international investigations covering a broad range of law firm practice areas.  Prior to his private sector experience, Don served more than 28 years in federal law enforcement with the DEA, IRS and the Office of Labor Racketeering-Office of Inspector General, U.S.D.O.L 


Relevant Experience


  • Former Enforcement Assistant for DEA supervising Europe and Near East enforcement and intelligence operations.
  • Supervisor with the Office of Labor Racketeering, managing and conducting complex white collar financial investigations involving traditional organized crime's infiltration of legitimate businesses, labor organizations and employee benefit plans.
  • Assignment to the U.S. Senate Permanent Subcommittee on Investigations chaired by Senator Sam Nunn, conducting oversight investigations involving the efficiency and economy of all branches of government and investigations to detect fraud, collusion, corruption and conflicts of interest by government agencies.
  • Supervising case agent on one of the largest health care fraud investigations ever prosecuted by the U.S. Department of Justice.
  • 19 years of experience managing and conducting private sector investigations.
  • Selected in 1988 and 1990 by the U.S. Justice Department as the "Outstanding Federal Law Enforcement Officer" in the Southern District of Florida.