Chad Bianco, the Riverside county sheriff, has halted a contentious investigation into a alleged voter fraud that has drawn opposition from the state’s attorney general.

The move marks a major reversal for Bianco, a prominent Donald Trump supporter who is one of the top two Republican candidates running for the governorship of California.

“We are on hold because of the politically motivated lawsuits and court filings,” Bianco said in a statement, according to ABC 10 News.

Bianco has spearheaded a lone wolf investigation for months into allegations that votes were unlawfully cast in last year’s election that resulted in the passage of Proposition 50.

The proposition, championed by Gavin Newsom, the governor, allowed the state to gerrymander congressional districts in favor of Democrats, in response to similar changes in Republican-dominated states such as Texas.

A group called the Riverside Election Integrity Team, comprising local residents, says that there is a difference 45,896 votes between the final vote tally and handwritten records of hand-counted tallies in the county.

Local electoral officials have dismissed those concerns, saying the citizen group misunderstood how to interpret the raw data, including the lack of precision of hand-counted tallies. According to state officials, the actual difference was only 103 votes.

Bianco recently seized more than 650,000 ballots from the election, over the objections of state officials.

Rob Bonta, the California attorney general, asked the state supreme court on Friday to stop Bianco’s investigation, arguing Bianco did not have the legal authority to seize the ballots. The petition described the seizure as an “unprecedented constitutional emergency”, according to the Los Angeles Times.

Bianco’s ballot seizure and maverick probe also face a lawsuit filed by UCLA’s Voting Rights Project.