Dietrich L. Snell

Dietrich L. Snell is a partner in the Litigation Department and co-chair of the White Collar Defense & Investigations Group. Dieter has extensive experience in law enforcement-related matters spanning a wide range of disciplines. He has both federal and state level prosecutorial and investigative experience, having served for nearly two decades as an Assistant U.S. Attorney; as New York Deputy Attorney General; and as Senior Counsel to the National Commission on Terrorist Attacks Upon the United States (the 9/11 Commission).

Clients and Areas of Concentration

Dieter’s clients include corporations and senior executives involved in civil and criminal investigations and prosecutions performed by federal and state law enforcement and regulatory authorities, in such diverse areas as

  • money laundering
  • foreign assets control
  • antitrust
  • false claims
  • Foreign Corrupt Practices Act (FCPA)
  • securities fraud (including New York's Martin Act)
  • civil rights
  • environmental law
  • online gambling


He frequently handles sensitive internal investigations for corporate clients and other entities. Dieter’s practice also includes commercial litigation in both federal and state court.

Prosecutorial Experience

As the New York Deputy Attorney General, Dieter was responsible for the investigation, litigation and regulatory activities performed by the Division of Public Advocacy under former Attorney General Eliot Spitzer. He supervised approximately 300 professional staff and oversaw complex cases and investigations involving:

  • Unlawful discrimination in lending, housing, and employment;
  • Bid rigging and other deceptive business practices by major participants in the insurance industry;
  • Securities law violations stemming from market timing activities within the mutual fund industry;
  • Conflicts of interest between research and investment banking functions of major Wall Street firms and the negotiation of a settlement between those firms and federal, state, and industry regulators;
  • Violations of the Clean Air Act by power plants and challenges to related Environmental Protection Agency rulemaking;
  • Federal court litigation over preemption claims by the Office of the Comptroller of the Currency regarding enforcement of the federal Fair Housing Act;


Before joining the New York Attorney General’s office, Dieter served for 11 years as Assistant U.S. Attorney for the Southern District of New York, notably handling the successful prosecution of 1993 World Trade Center bomber Ramzi Yousef for Yousef’s role in the 1994-95 plot to destroy 12 passenger jets in midair, as well as cases involving securities and commodities, bank and computer fraud, narcotics, money laundering, and racketeering offenses. As Deputy Chief Appellate Attorney, he supervised the preparation and submission of briefs to the U.S. Court of Appeals for the Second Circuit.

The 9/11 Commission

In his role as Senior Counsel to the 9/11 Commission, Dieter led the team assigned to investigate the plot that culminated in the September 11 attacks. He negotiated with the law enforcement, intelligence and diplomatic communities regarding access to documents, evidence, and witnesses; reviewed voluminous classified and unclassified materials; conducted witness interviews; advised commission members and assisted them at public hearings; and drafted and edited substantial portions of The 9/11 Commission Report.