(Adds details on case, background on FBI agent)
By Nate Raymond
NEW YORK, Jan 4 (Reuters) - U.S. prosecutors on Wednesday identified the FBI agent who they say admitted to leaking information to reporters about an insider trading probe involving a Las Vegas sports gambler and golfer Phil Mickelson.
David Chaves, a Federal Bureau of Investigation coordinating supervisory special agent, was named in court papers filed in Manhattan federal court as the agent prosecutors say leaked details about the probe of gambler William "Billy" Walters.
Prosecutors have said the agent, who they previously had not identified, admitted on Dec. 6 to being a "significant source" of information about the investigation in 2013 and 2014 for reporters at The Wall Street Journal and The New York Times.
Those newspapers published a series of reports beginning in 2014 about the investigation, two years before prosecutors in May brought insider trading charges against Walters, who has built a fortune as a sports bettor.
The leaks are now the subject of a criminal investigation by the Justice Department's Office of the Inspector General, prosecutors disclosed Dec. 21. Walters' lawyers are meanwhile expected to seek the case's dismissal as a result of the leaks.
Chaves, who oversaw the FBI squad that conducted the investigation, has not been charged in connection with the leaks. His lawyer did not immediately respond to requests for comment. A lawyer for Walters declined comment.
Chaves previously has been involved in several high-profile securities fraud matters, including an FBI probe into insider trading in the hedge fund industry dubbed "Operation Perfect Hedge" that resulted in dozens of people being charged.
In Walters' case, prosecutors say the gambler made more than $40 million through insider trading on tips supplied by Thomas Davis, the former chairman of Dean Foods Co.
The U.S. Securities and Exchange Commission in a related civil case said Mickelson, who has won three Masters pro golf titles, at one point bought Dean Foods' stock on a recommendation by Walters, to whom he owed money.
Mickelson was not accused of wrongdoing, but he reached an agreement with the SEC to pay back $1.03 million the regulator said he earned trading shares of Dean Foods. Davis has pleaded guilty. Walters is scheduled to face trial on March 13.
Lawyers for Mickelson and Davis did not immediately respond to requests for comment on Wednesday.
The case is U.S. v. Davis et al, U.S. District Court, Southern District of New York, No. 16-cr-338. (Reporting by Nate Raymond in New York; Editing by Tom Brown)