Mayor Adrian Fenty started his Wednesday with a police department photo-op, but by the afternoon he was fielding questions about what authorities called the largest rip-off in city history while attempting to keep public confidence in his government.

The pilfering of roughly $16 million by higher-ups in the Office of Tax and Revenue, if proven true, is “one of the most serious breaches of the trust of the public,” Fenty said during a news conference with federal authorities. And with quick prosecution and punishment, he said, the District will “send a very strong signal to the residents of the District of Columbia that any alleged corruption will not be tolerated.”