The San Bernardino County sheriff confirmed the investigation while giving few details, the Los Angeles Times reported.
"Several months ago at the request of San Bernardino city officials, the San Bernardino County Sheriff's Department, along with the San Bernardino Police Department and the district attorney's office began an investigation related to allegations of possible criminal activity within departments of the San Bernardino city government," the statement said. "The investigation is continuing, and details will not be released at this time. Updates will be provided as new information becomes available."
San Bernardino, a major center in Southern California's Inland Empire -- east of Los Angeles -- is the third city in the state to go into bankruptcy in the past month. The city council approved a Chapter 9 filing Tuesday, using the section of the federal bankruptcy code that applies to local governments.
Stockton, one of the major centers in the Central Valley, and Mammoth Lakes, a small town in the Sierra Nevada mountains, have also sought bankruptcy protection.