San Mateo County Sheriff Ken Binder has appointed Ryan Monaghan as assistant sheriff, the same position Monaghan was fired from under former Sheriff Christina Corpus.
“I’m excited to share that Ryan Monaghan is returning to the San Mateo County Sheriff’s Office to serve in the key role of Assistant Sheriff of Support Services,” Binder said in a statement Wednesday.
Monaghan is the latest member of Corpus’ former executive team to be rehired by Binder, who was appointed to the role of sheriff last month after the Board of Supervisors ousted Corpus in October, concluding a year of scandal that rocked the San Mateo County Sheriff’s Office.
Corpus was fired after a judge determined that there were multiple grounds for dismissal and after voters had given the board the authority to remove her. Among the allegations were that she was neglecting her duties as sheriff by engaging in retaliation and misusing public funds by having a conflict of interest in the hiring of her former chief of staff.
“I’m honored to return to the Sheriff’s Office and consider it a privilege … to serve the diverse communities that make San Mateo County such a remarkable place.”
Ryan Monaghan
Monaghan was one of several current and former Sheriff’s Office members who accused Corpus of retaliation.
He was fired from his assistant sheriff position by Corpus in September 2024, a move that Corpus said was due to growing mistrust in him.
She accused him of leaking information to County Executive Mike Callagy, who subsequently tried to block Monaghan’s firing out of concern that it could be seen as unlawful retaliation because he cooperated in an independent investigation into mounting claims of misconduct by Corpus.
Led county effort to combat human trafficking
After his firing, Monaghan remained a county employee working in the District Attorney’s Office, where he led a county-wide, multi-agency effort to combat human trafficking.
As assistant sheriff of support services under Binder, Monaghan will oversee the Professional Standards Bureau in the Sheriff’s Office, which manages hiring and internal affairs investigations. He will also support the Fiscal Services Bureau, the Forensic Laboratory and the Technical Services Unit.
“I’m honored to return to the Sheriff’s Office and consider it a privilege to work alongside the dedicated men and women of the Sheriff’s Office and to serve the diverse communities that make San Mateo County such a remarkable place,” Monaghan said in a statement.
Monaghan has more than three decades of law enforcement experience. He served as Tiburon’s police chief after spending 27 years in the San Mateo Police Department.
He will be joining alongside Undersheriff Chris Hsiung, who was also a member of Corpus’ former executive team. Hsiung abruptly stepped down from his role as Corpus’ undersheriff a few months before the turmoil in the Sheriff’s Office entered the public eye.
Monaghan will begin his duties Sunday.
