Riverside County Sheriff Chad Bianco, who is a leading Republican candidate for governor, has seized more than 650,000 ballots from last November’s election and is investigating whether they were fraudulently counted.

“This investigation is simple: Physically count the ballots and compare that result with the total votes recorded,” Bianco said at a news conference Friday.

The unusual probe drew a sharp rebuke from California Atty. Gen. Rob Bonta, who said in a statement Friday that it is “unprecedented in both scope and scale” and appears “not to be based on facts or evidence.”

“There is no indication, anywhere in the United States, of widespread voter fraud,” Bonta said. “Counts, recounts, hand counts, audits, and court cases all support this.”

According to Bonta’s office, Bianco’s department on Feb. 26 seized about 1,000 boxes of ballot materials in Riverside County related to the November election for Proposition 50, which temporarily redrew the state’s congressional districts to favor Democrats in response to partisan redistricting in Republican states, including Texas.

The sheriff said his investigators are looking into allegations by a local citizens group that “did their own audit” and found that the county’s tally was falsely inflated by more than 45,000 votes — a claim that local election officials have rejected.

The investigation comes as President Trump — who remains fixated on his 2020 election loss — continues to amplify election conspiracy theories and has repeatedly called for the federal government to “nationalize” state-run elections to counter what he says is widespread fraud.

Bonta and California Secretary of State Shirley Weber, both Democrats, have vowed to fight federal interference that could affect voting in California, including efforts to seize election records, as the FBI recently did in Georgia.

Bianco is an outspoken Trump supporter who said in an endorsement video in 2024 that, after 30 years of putting criminals in jail, he figured it was “time to put a felon in the White House — Trump 2024, baby” — referencing Trump’s conviction by a New York jury for falsifying business records while paying hush money to a porn actor.

Bianco’s investigation, which includes all the ballots cast in Riverside County in November, raises questions about how he would handle the election denialism movement if elected governor.

A poll released last week by UC Berkeley’s Institute of Governmental Studies and co-sponsored by The Times showed Bianco and conservative commentator Steve Hilton leading the crowded field of gubernatorial candidates by slim margins, in a left-leaning state.

Last fall, Proposition 50 passed in Riverside County with 56% of the vote — a margin of more than 82,000 ballots.

A citizens group called the Riverside Election Integrity Team has said it performed an audit finding that 45,896 more ballots were counted than were cast.

In a lengthy February presentation to the Riverside County Board of Supervisors, Registrar of Voters Art Tinoco disputed that figure, saying it was based on a misunderstanding of raw data that had not been fully processed.

The actual discrepancy, Tinoco said, was 103 votes, a variance of 0.016% that was far below what he said was the state’s preferred 2% margin of error for certifying results.

Bianco on Friday said that there “is no acceptable error, small or large, in our elections.”

The sheriff did not name the Riverside Election Integrity Team, but his description of the allegations brought to him by “a group of citizen volunteers” matched theirs.

Bianco said the investigation was “not a recount” for the Proposition 50 contest and was “just as much to prove the election is accurate as it is to show otherwise — we will not know until the count is complete.”

Bonta said his office has “attempted to work cooperatively” with the Sheriff’s Department to understand the basis for the probe. The sheriff, Bonta said, “has delayed, stonewalled, and otherwise refused to work with us in good faith” and failed to provide most of the requested documents.

“We’re concerned that there is not sufficient justification for seizing every ballot that was cast in this very largely populated county,” an official in Bonta’s office said in an interview Friday night.

In a March 4 letter to Bianco, the attorney general cited Bianco’s plan to use Sheriff’s Department staffers, “who are not trained and have no experience,” to count the ballots.

“Let me be clear: this is unacceptable,” Bonta wrote. “Your decision to seize ballots and begin counting them based on vague, unsubstantiated allegations about irregularities in the November special election results sets a dangerous precedent and will only sow distrust in our elections. You are also flagrantly violating my directives.”

At his news conference Friday, Bianco fired back by calling Bonta “an embarrassment to law enforcement.”

A Riverside County Superior Court judge, Bianco said, has ordered the appointment of a special master to oversee the ballot count.

In a statement Friday, Secretary of State Weber said “the Sheriff’s assertion that his deputies know how to count is admirable. The fact remains that he and his deputies are not elections officials and they do not have expertise in election administration.”