A top official tasked with keeping San Francisco's streets clean was arrested by the FBI and charged with corruption.

San Francisco Public Works Director Mohammed Nuru is being held on $2 million bail for the charges. An entrepreneur and friend to Nuru was also arrested and held on $2 million bail.

Ironically, he went by the moniker "Mr. Clean SF" on Twitter.

Federal officials relayed the details of the case against Nuru in a media briefing on Tuesday after his arrest in January. They said that he had agreed to cooperate with the investigation, but later violated the agreement and was re-arrested.

Nuru is accused of offering a bribe, accepting lavish gifts from a developer, and supplying inside information to a friend.

Officials indicated that the evidence against Nuru involved undercover agents and FBI wiretaps.

He spearheaded the city's "poop patrol" efforts to clean up fecal matter in the city, which had become an epidemic and the fodder for embarrassing headlines.

Nuru had been in charge of the public works department since 2012 and oversaw its $312 million budget. He was placed on administrative leave in the wake of the charges being revealed to the public.

Here's the FBI media briefing: