The resignation of the head of Florida's Department of Children and Families presents Gov. Jeb Bush with a monumental task: finding someone to revive an agency rocked by a string of children's deaths and disappearances.

Kathleen Kearney resigned Tuesday, four months after the department learned a 5-year-old girl in its care had been missing for more that a year -- and in the wake of a 2-year-old's death and the agency's inability to find dozens of missing children.

Bush accepted Kearney's resignation, but did not say when he would appoint a replacement.

Jack Levine, president of the Center for Florida's Children, said finding a new secretary will be the "most Herculean task" of Bush's term in office.

"To think that there is someone out there who is ready, willing and able to accept the job of heading this department which is under such tension and presiding over so many tragedies is a true test of the governor's leadership," Levine said. "He has to find someone who can lift the morale internally and rebuild the trust externally of the department under fire."

Bush defended Kearney after her resignation, much like he has throughout all the turmoil.

"All Floridians owe her a debt of gratitude for her public service," he said.

Kearney, who steps down Sept. 3, earned $112,797 and received a 3.5 percent raise last year. According to the South Florida Sun-Sentinel, many of her administrators received raises of up to 10 percent over the past two years, increasing their salaries to more than $100,000 a year. Kearney did not respond to calls for comment on the increases.

In her resignation letter to Bush, Kearney said: "I would like to believe that that during my stay here it can be said that: she believed, she hoped, she tried, she failed often enough, but with God's grace, she often accomplished more than she rationally could have dreamed."

The agency has been under fire since it was revealed that Rilya Wilson had disappeared while in state custody. The little girl has been missing since January 2001 and no caseworker had checked on her for 15 months.

Kearney's only mention of Rilya's case in the letter was to say that her department had been aggressively working to improve the tracking of children.

Kearney, a former prosecutor, was a juvenile court judge in Fort Lauderdale presiding over child abuse and neglect cases when Bush appointed her in 1999. He had promised during his 1998 campaign that he would solve problems at the agency. She came under criticism as more and more problems at the agency were revealed.

Besides Wilson's disappearance, a caseworker last month filed a report saying 2-year-old Alfredo Montez was fine only to have police find the boy had been beaten to death -- before the worker's supposed visit.

Last month a child welfare worker was arrested after police said she was passed out drunk in her car with a child in the back seat. On Tuesday, the South Florida Sun-Sentinel, which reported over the weekend it found nine children DCF claimed were missing, filed suit to force the agency to open case files of 22 children missing under DCF care.

DCF spokesman Bob Brooks said Wednesday the agency had not been served with the lawsuit and could not comment.