LOS ANGELES — Robert Rizzo, the former city administrator of Bell, Calif., accused of looting millions from city coffers, pleaded no contest to all 69 charges against him on Thursday, prosecutors announced.

The judge, Judge Kathleen Kennedy, indicated that Mr. Rizzo would be sentenced to 10 to 12 years in prison, which would be the longest sentence in a Los Angeles County public corruption case since at least 2001, according to the district attorney’s office.

“Although we were prepared to go to trial and felt confident we could convict Mr. Rizzo of all charges, we are pleased he chose to admit his guilt and accept full responsibility for the irreparable harm he caused the people of Bell,” Jackie Lacey, the district attorney, said in a statement.