Laura Coulthard, director of Sacramento County's Child Protective Services, has taken an extended leave of absence from the agency, officials confirmed Tuesday.
No timetable has been set for her return, said spokeswoman Laura McCasland. McCasland declined to cite a reason for Coulthard's departure, calling it a "personnel issue."
Coulthard did not return phone messages from The Bee.
Kim Pearson, one of the agency's three division managers, will fill in during Coulthard's absence. Pearson has been with the agency for 14 years, working her way up from social worker, said Mc-Casland.
"She has a lot of experience, and we will continue moving forward," McCasland said.
Coulthard has overseen CPS since 2007, during an often tumultuous time in which the agency faced steep budget and staffing cuts and was accused of faltering in its mission to protect children at risk of neglect and abuse.
The agency, which currently employs 769 workers, has lost about a third of its staff since July 2009.
Coulthard promised big changes at CPS after scathing reports in 2009 by a grand jury and a private consulting firm. Both cited internal failings that allegedly left the county's most vulnerable children in danger.
A grand jury report last year concluded that the safety of those youngsters remained in jeopardy but indicated the agency was moving in the right direction.
After a Bee investigation into the 2008 death of 4-year-old Amariana Crenshaw highlighted the agency's missteps, Coulthard acknowledged mistakes and vowed to fix them.
She told county supervisors in December that CPS has improved its response to crisis calls. But she also said social workers who handle abuse claims are struggling with higher caseloads and are taking longer to respond to abuse complaints that do not require a response within 24 hours.