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J. Gregory Deis

J. Gregory Deis

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Securities Investigations: Internal, Civil and Criminal

Securities Investigations: Internal, Civil and Criminal

Current Issues in Internal Corporate Investigations

Global Investigations Review 2016

J. Gregory ("Greg") Deis is a former federal prosecutor whose practice focuses on white-collar defense, internal investigations and complex commercial litigation.

Greg regularly represents clients in DOJ, SEC and other criminal/regulatory investigations, including investigations involving the FCPA, accounting/financial statements, health care, tax, money laundering and environmental offenses. Greg's white-collar defense experience includes cross-border DOJ/SEC investigations in China, Brazil and India. Greg has also  led internal investigations for a variety of clients, including cross-border investigations involving alleged misconduct in Asia, Africa and South America.

Greg is a seasoned trial lawyer, having tried many criminal and civil cases in federal and state court and in arbitration, along with serving as lead counsel in numerous criminal and civil appeals. Greg's complex commercial litigation experience involves various areas of law, including the False Claims Act, RICO, tax controversy, environmental law, federal securities law, shareholder derivative claims, trademark law, UCC and defamation.

Prior to rejoining Mayer Brown, Greg served as an Assistant US Attorney in Chicago, assigned to the Public Corruption section. Greg prosecuted numerous public officials and law enforcement officers with fraud, bribery, extortion and tax offenses, including the bribery prosecution of an Illinois state representative – which resulted in the first expulsion from the Illinois House since 1905. His trial experience includes the month-long trial of William Cellini, a long-standing political insider in Illinois convicted of extorting campaign contributions for then Governor Rod Blagojevich. In addition to his corruption experience, Greg investigated and prosecuted a wide range of federal criminal cases involving complex financial fraud, procurement fraud, money laundering, computer offenses and international drug trafficking.

Greg maintains an active pro bono practice, including serving as a Panel Attorney for the Federal Defender Program in Chicago, representing indigent defendants in federal criminal proceedings.

Greg has been an adjunct professor of criminal procedure and trial advocacy at DePaul University College of Law and serves on Law360’s White Collar Editorial Advisory Board. Greg began his legal career as a law clerk for the Honorable Deanell Reece Tacha, Chief Judge of the US Court of Appeals for the Tenth Circuit.

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