The video in the player above is from a previous report.
The deputies union and Supervisor Ray Mueller confirmed Fox's resignation.
The Sheriff's office tells ABC7 News it "does not comment on personnel matter," and that Sheriff Corpus would "like to thank him for his dedicated service to the San Mateo County community and she wishes him the best in his future endeavors."
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Fox was promoted to his role of assistant sheriff in September, the deputies union said. According to his biography page on the department's website, he joined the office in 2023 and has more than 25 years of law enforcement experience in the area.
ABC7 News reached out to Fox for comment about his departure and will update this story if we hear back.
Additionally, Mueller confirmed to ABC7 News that an unnamed officer also left the sheriff's office, after he was asked to arrest Deputy Carlos Tapia. On Tuesday, the sheriff's department arrested Carlos Tapia, who is also president of the Deputy Sheriff's Association union, on two separate charges.
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Tapia is one of many deputies who has criticized the sheriff and her office.
It all follows a week of tumult in the department after a nearly 400-page investigative report accused his boss, Corpus, of a pattern of misconduct. Some of the allegations include abuse of power, retaliation, having an inappropriate relationship with her chief-of-staff, and using racist and homophobic slurs. The report was prompted by internal complaints against Corpus and commissioned in July. The county tapped retired Santa Clara County Judge LaDoris Cordell to look into fifteen allegations from current and former employees in the sheriff's department.
Via phone call, Corpus told ABC7 News she feels she has been unfairly targeted in this investigation and denies all wrongdoing.
Corpus has remained defiant throughout the week, refusing to cede to mounting pressure for her to resign. During a Wednesday meeting in which the board of supervisors unanimously passed a vote of no confidence in her, Corpus stormed out of the meeting after brief remarks in which she called the report a "hatchet job" that is "filled with lies."
During the meeting, supervisors were also about to remove the position of Corpus' chief of staff, Victor Aenlle, before she announced she would promote him to assistant sheriff. After that, the board passed a resolution directing its legal counsel to look into whether Corpus legally has the ability to do that.
Read the full investigation report below or click here.
Editorial Note: This article was updated to remove a report of Undersheriff Dan Perea resigning.
This is a developing story, check back for updates.