Updated

Attorneys for a defendant arrested in an FBI sting involving state Sen. Leland Yee claim the FBI removed its lead agent from the corruption case over unspecified financial improprieties.

The claim was made Thursday in a filing by lawyers for Keith Jackson, a former political fund-raiser for Yee, a San Francisco Democrat.

Defense attorneys argue that the FBI sting operation was part of a wide-ranging federal effort to entrap targets and included lavishing Jackson with tens of thousands of dollars for lawful actions.

The filing says FBI wiretap applications in the case revealed that the unidentified FBI agent had been removed from the case following an internal probe of FBI financing and record-keeping. No further details were included.

The U.S. attorney's office has declined comment on the filing.