Henry Garcia made the sudden move at Tuesday night's City Council meeting.
"We have accomplished much in this community over the past several years," Garcia said in a statement."The level of collaboration between elected officials, community stakeholders and staff leaves the City extremely well positioned for the future. I have found it professionally and personally rewarding to be part of such a successful, community-driven team."
This comes as the city is embroiled in a corruption investigation involving Mayor Tom Owings and four fellow council members.
The Riverside County District Attorney's Office says local and federal investigators are looking into possible influence peddling, campaign violations and political corruption.
The City Council has appointed Assistant City Manager Michelle Dawson as City Manager, effective immediately.