Dana Williamson, a top California political strategist with ties to the state’s governor, Gavin Newsom, and gubernatorial hopeful Xavier Becerra, pleaded guilty on Thursday to fraud charges, an admission that is poised to fuel other candidates’ attacks in the race.

Federal authorities say Williamson conspired to steal $225,000 from a dormant campaign account belonging to Becerra, who was not named in the plea deal, and divert the money to his chief of staff, Sean McCluskie.

The funds were disguised as pay to McCluskie’s spouse for nonexistent work. McCluskie reportedly took a pay cut to join Becerra when he became the US secretary of health and human services in 2021.

McCluskie took a plea deal last December.

Becerra has maintained he did not know about the scheme, but his opponents have sought to link him to the corruption investigation.

“We know that Xavier Becerra likely broke state law, and now he’s at the center of an ongoing criminal investigation,” billionaire Tom Steyer, one of Becerra’s top rivals in the governor’s race, said in a statement after Williamson’s guilty plea. “Democrats cannot afford to wake up on June 3 and discover we’ve got a criminal on our hands. Xavier Becerra should not be our governor, and we can’t risk having him as our nominee.”

Katie Porter, the former congresswoman also running for governor, said earlier this week that Becerra’s proximity to the scandal made him “too big of a risk” for voters.

Becerra’s campaign did not immediately return the Guardian’s request for comment.

Williamson wielded considerable influence in Sacramento politics. She served as chief of staff to Newsom and cabinet secretary for Newsom’s predecessor, Jerry Brown.

Williamson also pleaded guilty to making false statements about the campaign fund scheme and filing false tax returns, in which she claimed roughly $1.7m in personal expenses as business deductions, according to law enforcement officials.

A court date regarding her sentencing has been set for July. Williamson is facing up to 38 years in prison.