The charges were announced Tuesday at an unusual news conference with King County Executive Ron Sims, Seattle Police Chief Gil Kerlikowske, King County prosecutor Norm Maleng, and the people who run the adult and the juvenile detention facilities.

After rumors circulated of sexual misconduct at the juvenile facility, Sims asked Maleng and the Seattle Police Department to assist in the investigation.

Kerlikowske says the investigation focused on nine juvenile detention guards and two others who are assigned to the facility. Three individuals remain under investigation, while one was charged Tuesday: 34-year-old Lydia Jo Korolak. The charging papers say she had a sexual relationship with two juveniles, identified only as L. J. and J.H.

If convicted, she would face five years in prison. Four other departmental employees who allegedly knew of the abuse but did not take appropriate action face administrative discipline.

The jail administrators say they believe the problems are history, but the National Institute of Corrections will be asked to survey the juvenile facility and report to county officials.

"King County has a zero tolerance for illegal, unethical, offensive and inappropriate conduct on the part of our jail employees," King County Executive Ron Sims said in announcing the charges today,

Prosecutor Norm Maleng added: "In a criminal justice system, and particularly in a juvenile justice system, it is intolerable for someone in a position of authority to take advantage of a young detainee."

Charging papers says the sex happened at the juvenile detention facility between April 2001 and April 2003.

There are no cameras in the cells, and with a key, a guard can get into a cell without any sound -- no clunk, no buzz. Officials say security studies are now under way, including the possible installation of cameras.

One person who sat in on a disciplinary hearing three years ago tells KOMO 4 News that there is a twist in this story: The woman charged today was investigated in 2003.

It involved J.L., who had then been transferred to another facility. Korolak was investigated for corresponding with and sending money to J.L. in the new facility.

The panel decided Korolak should get a letter of corrective counseling.

Kerlikowske confirms the Korolak case was not on the original list to be investigated. Police asked for copies of all investigations within a 10-year period.

Detectives say at the time of the 2003 hearing, there were no questions about conduct involving J.L. and Korolak at juvenile hall. So detectives reinterviewed her.

The charging papers say Korolak then admitted having sex with a boy named L.J. in his cell (in 2001).

When investigators hinted about a second case, Korolak allegedly said: You mean J.H.?

Although only one person has been charged, there may be others involved. Kerlikowske says four other cases remain under investigation. They apparently involved three other employees of the juvenile hall.

All have been placed on administrative leave, pending completion of the investigation.