(KRON) -- San Mateo County Assistant Sheriff Matthew Fox has resigned, the San Mateo County Deputy Sheriff's Association said on Friday. Fox's abrupt resignation comes amidst an ongoing controversy surrounding San Mateo County Sheriff Christina Corpus. This week the Board of Supervisors called on the sheriff to resign amid allegations of a toxic work environment revolving around Corpus' romantic partner. Recalled Alameda County DA issues fiery statement, refuses to concede Corpus allegedly has an inappropriate relationship with her chief of staff, Victor Aenlle, according to the county's independent investigator. Elected in 2022, Corpus has dug in her heels, refused to step aside, and denied the allegations. San Mateo County Sheriff Christina Corpus speaks at a news conference following the Half Moon Bay mass shooting. (AP Photo/Jeff Chiu) On Wednesday, a defiant Corpus promoted Aenlle to assistant sheriff "effective immediately." This followed the board of supervisors eliminating Aenlle's executive director of administration position. Fox, according to the San Mateo County Sheriff's Office website, is a 25-year law enforcement veteran who served with the Daly City Police Department previously. He joined the sheriff's office in 2023. "Like Sheriff Christina Corpus, he believes that fostering a culture of change is vital for creating a new era of policing that prioritizes community needs and collaboration," his official bio reads.