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Sigal Mandelker is a member of Proskauer’s White Collar Defense & Investigations Group and recently launched the firm’s Corporate Defense and Disputes Blog ( Leveraging her broad experience in senior government positions at the U.S. Department of Justice and the U.S. Department of Homeland Security, Sigal offers a nuanced understanding of domestic and international enforcement matters, crisis management, appellate litigation and regulatory matters.

Sigal represents individual and corporate clients in connection with government investigations and prosecutions, including white collar criminal defense, the False Claims Act, the Foreign Corrupt Practices Act (FCPA), anti-money laundering matters, Securities and Exchange Commission (SEC) enforcement matters, securities litigation, internal investigations, public corruption issues and cyber security matters.

Sigal’s recent representations include:

  • Representing financial institutions and executives in connection with investigations by the Department of Justice, the SEC and the Federal Deposit Insurance Corporation
  • Representing health care providers in health-care-fraud investigations including major, national investigations by the Department of Justice
  • Representing companies and individuals in connection with insider trading, ERISA-related fraud, public corruption and other criminal allegations
  • Conducting internal investigations for public and private companies in connection with allegations of misconduct
  • Advising companies on FCPA matters
  • Defending against complex civil lawsuits

Before joining Proskauer, Sigal served in a number of high-ranking positions at the Department of Justice and the Department of Homeland Security. From 2006 to 2009, she was Deputy Assistant Attorney General in the Criminal Division of the Department of Justice, where she oversaw four major sections, including the Computer Crime and Intellectual Property and the Domestic Security sections, and over 120 lawyers and other professional staff. She supervised a number of high-profile and complex domestic and international prosecutions, including some of the nation’s most significant cases, represented the Department internationally, including before the United Nations, and testified before Congress numerous times.

In various enforcement areas, Sigal coordinated the Department’s work with the FBI, DHS, U.S. Immigration and Customs Enforcement, the U.S. Secret Service, the State Department, the Office of the United States Trade Representative, the Department of Commerce, the White House, the National Security Council, the Homeland Security Council and other government agencies.

Sigal also served as Counselor to the Secretary of Homeland Security, as an Assistant U.S. Attorney in the Southern District of New York, and as a Counsel to the U.S. Deputy Attorney General. She began her prosecutorial career at the Department of Justice in the Criminal Division as a counsel to the Assistant Attorney General.

Sigal clerked on the United States Supreme Court for Associate Justice Clarence Thomas and on the United States Court of Appeals for the Fifth Circuit for Judge Edith H. Jones.

Sigal is a frequent speaker on cross-border criminal investigations, the Foreign Corrupt Practices Act, the False Claims Act, the Supreme Court and cyber security.