San Francisco Mayor Ed Lee is reacting with a shrug of the shoulder to news that an undercover FBI agent donated $10,000 to his campaign and was awarded with a meeting in his office, reports CBS San Francisco

The accusation comes from the defense attorneys for Raymond Shrimp Boy Chow who questions why their client is being prosecuted for racketeering when Mayor Ed Lee and other politicians are being given a pass.

Since then, criminal prosecutors and the city attorney’s office have opened an investigation into whether the racketeering case reaches into city hall, according to unidentified sources quoted by the

SF Chronicle.

“It’s an allegation,” said Lee. “You know we don’t know that for a fact. We’ve checked every donation that we have. . .We do not know of any individual who didn’t legitimately give to our campaign, And those that we did uncover we returned them so they were clean.”

Documents filed in court by Chow’s attorney Tony Serra show the FBI did target Lee in its probe that netted not only Chow, but Assemblyperson Leland Yee and former school board President Keith Jackson. Both Yee and Jackson have pleaded guilty to the charges.

Serra contends that Mayor Lee’s campaign accepted $20,000 in exchange for political favors. No evidence has yet been presented to back that allegation.

You can read about the allegations in detail in the SF Chronicle.

You can hear more of Mayor Lee’s response in the clip below.