Thomas P. O’Brien is a Litigation partner with Paul Hastings in Los Angeles, where he focuses on white collar litigation and trial work. He focuses his practice on representing clients in federal and state investigations, including Foreign Corrupt Practices Act (“FCPA”), False Claims Act (“FCA”) and other corporate compliance matters, international business disputes, and high-stakes civil litigation. As the former United States Attorney for the Central District of California, Mr. O’Brien has vast experience as a trial attorney, having tried 85 cases, both criminal and civil, in federal and state court.
Since joining Paul Hastings, Mr. O’Brien has represented national and multi-national companies in civil actions with billions of dollars in dispute, federal and state government inquiries and grand jury investigations, and led complex corporate internal investigations. Mr. O’Brien has also successfully represented individual corporate leaders and foreign heads of state in civil, criminal, and regulatory proceedings.
During his tenure as U.S. Attorney prior to joining Paul Hastings, Mr. O’Brien was responsible for federal criminal and tax investigations and prosecutions and all civil matters involving the United States—in the largest federal district in the country. Under his leadership, his office filed the most felony cases in the history of the Central District, and increased complex case filings by 50 percent. The office also filed the largest RICO case ever against a motorcycle gang and, in a national first, seized the gang’s trademark.
Before he was confirmed as U.S. Attorney, Mr. O’Brien served for more than two years as the chief of the Criminal Division. In that capacity, he oversaw several high-profile espionage cases, helped bring the first treason case in the nation since World War II, supervised several high-profile public corruption and civil rights cases, charged several cyber crime statutes which had not been charged in the nation, and executed some of the largest fraud cases in the United States. He was the only criminal chief in many years who tried cases during his tenure.
Before serving as Criminal Chief, he was a Line Assistant United States Attorney for four years before rising to chief of the Civil Rights Section, where he personally investigated and prosecuted numerous cases, including federal hate crimes, human trafficking violations, and police misconduct cases.
- Mr. O’Brien represents a foreign conglomerate in a high-profile investigation involving allegations of international trade secret theft.
- Mr. O’Brien is currently leading the defense of a university professor in a high-profile felony prosecution of labor code violations. Early in the prosecution, Mr. O’Brien and his team filed an innovative motion challenging the sufficiency of probable cause supporting the arrest warrant and alleging that the affiant and lead investigator omitted material facts from the magistrate when the warrant was issued.
- Mr. O’Brien represents the police chief of a local city who faced civil charges filed by the state Attorney General as part of allegations against an entire city council and several administrators for defrauding taxpayers and wasting taxpayer monies. In a case described by numerous media outlets as one of the biggest corruption cases in the nation, and despite the extreme public outcry attacking his client, Mr. O’Brien and his team convinced the court to dismiss the complaint with prejudice.
- Mr. O’Brien represents a physician with a successful medical practice who is being investigated by the Department of Justice for claims of fraudulent billing. When Mr. O’Brien was brought onto the case, the investigation had been ongoing for several years, and the government had issued a final plea offer and expressed their intention to indict the client. Within weeks, Mr. O’Brien and his team conducted an investigation and presented new evidence to the Department of Justice. The Department of Justice decided to allow the statute of limitations run on the charges that they, only weeks earlier, intended to file.
- Mr. O’Brien represents a local airport commission in an investigation by the Federal Bureau of Investigation into allegations of corruption. Within months of being retained in this case, Mr. O’Brien managed to focus the government on the actions of other individuals and received a letter from the DOJ clearing his client.
- Mr. O’Brien led a team of attorneys in conducting an internal investigation at the request of a Southern California health center. That investigation, since closed, arose out of allegations that employees of that health center accepted improper benefits in exchange for referrals to certain patient facilities.
Accolades and Recognitions
- Received awards from many different organizations, including the Los Angeles City Council; Los Angeles Police Department; Federal Bureau of Investigation; Drug Enforcement Administration; United States Secret Service; Internal Revenue Service; United States Marshal’s Office; Santa Barbara District Attorney’s Office; United States Postal Service; United States Postal Inspectors and Office of Inspector General; Bureau of Alcohol, Tobacco, Firearms and Explosives; and the Los Angeles City Attorney
- Received the 2007 Anti-Defamation League Pacific Southwest Region’s Helene and Joseph Sherwood Prize for combating hate
- In October 2007, received the Attorney General’s Award for Exceptional Service—the highest award given by the Attorney General—for his role in investigating and prosecuting street gang members who committed hate-crime murders of African-Americans in Northeast Los Angeles
- Received the 2008 Immigration and Customs Enforcement Assistant Secretary’s Award for Excellence in Law Enforcement
Speaking Engagements and Publications
The Corporate Counselor: Indicting a Foreign Company: Satisfying the Technical Requirements of Criminal Rule 4 by Resorting to the Civil Alter Edo Doctrine, by Thomas P. O'Brien, Daniel Prince, and Kathryn C. Wanner, Winter 2012
- University of San Diego School of Law, J.D., 1993 (cum laude, Associate Editor of the San Diego Law Review)
- United States Naval Academy, B.S., 1981