Tomas Castella focuses his practice on government investigations and complex civil litigation. He has represented individuals, corporations, and professional firms in investigations and related civil suits in courts across the country. His clients span the technology, entertainment, transportation, and biotechnology industries. A dual citizen of the United States and Mexico, Tomas is a fluent Spanish speaker and has handled several matters focused on Latin America.

Tomas received his J.D. with honors from the University of Texas School of Law and his B.A. in Economics from Boston College. While at the University of Texas, he served on the executive board of the Texas Law Review and was selected to participate in the Criminal Defense Clinic. Prior to joining Williams & Connolly, Tomas clerked for Judge David A. Ezra of the U.S. District Court for the Western District of Texas and Judge Edward C. Prado of the U.S. Court of Appeals for the Fifth Circuit.

Representative Experience

Though all cases vary and none is predictive, Tomas’ experience includes:

  • Representing a multinational technology company in antitrust investigations conducted by the Federal Trade Commission (“FTC”), various state attorney generals, and foreign regulators. 
  • Representing a global media company in a criminal investigation by the U.S. Department of Justice (“DOJ”) and a related civil RICO lawsuit stemming from alleged conduct in South America. 
  • Defending an international law firm in a malpractice action brought by a Brazilian industrial conglomerate embroiled in a government corruption probe. 
  • Defending a biotechnology company in an antitrust lawsuit alleging that the company maintained a monopoly and/or agreed to restrain trade. 
  • Representing an international non-profit organization and its executives in a tax investigation and related civil litigation against the DOJ and Internal Revenue Service (“IRS”). 
  • Advising a South American diplomatic official on a U.S. privacy law issue. 
  • Representing a national accounting firm in a professional malpractice action against a title insurance company. 
  • Successfully winning asylum for a Salvadorian mother and young child who faced death threats from MS-13 and were separated at the U.S. border. Following protracted litigation and a contentious merits hearing, the judge ruled in their favor on multiple, independent grounds. 





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