HERCULES -- The City Council agreed Tuesday to urge state and county prosecutors to investigate potential criminal wrongdoing by a former top official and others who may have played parts in the city's financial meltdown of the late 2000s.

The former city manager, Nelson Oliva, was fined $70,000 in November by the state Fair Political Practices Commission for conflicts of interest and unreported gifts. Days earlier, Oliva and his family company, NEO Consulting Inc. (DBA Affordable Housing Solutions Group) agreed to settle a lawsuit with the city for $3.2 million. The amount is equivalent to the total of city contracts for housing, loan and construction management and administrative services that Oliva executed with NEO during his tenure as city manager, which lasted from April 2007 to January 2011.

Federal law enforcement officials have investigated off and on, but no one has been charged with a crime.

Tuesday's council discussion originated with a proposal by Councilman Bill Kelly to write a letter to Contra Costa County District Attorney Mark Peterson urging him to investigate potential criminal wrongdoing by Oliva.

Councilman Dan Romero expanded on that idea, urging the council to contact not only Peterson but also state Attorney General Kamala Harris, and to broaden the scope of the proposed investigation to others who may have committed criminal acts.

After some discussion, the council instructed City Attorney Patrick Tang to compose a letter to Peterson and Harris urging prosecution not limited to any one individual, and to allow residents to add their signatures.

Tang said he expects to post the letter on the city's website by the middle of next week. Residents will be able to sign the letter at Hercules City Hall.

The letter will go before the council at its next meeting Feb. 25 for formal approval and signature by all five council members.

Oliva and his attorney Richard Ewaniszyk could not be reached for comment.

Contact Tom Lochner at 510-262-2760. Follow him at twitter.com/tomlochner.