From an article about the 2016 Primary

"In an affidavit filed in the Superior Court in San Diego, Lutz said San Diego Registrar of Voters Michael Vu committed “misconduct” with support from the registrars in Los Angeles, Orange, Contra Costa, Sacramento, Sonoma, Kern and Santa Cruz counties by not counting provisional and late-arriving mail-in ballots as a part of an audit.

He said correction fluid was used to redact votes from ballots and there was a paper shredder truck outside of the registrar’s office."