TACOMA, Wash. -- Terapon Adhahn, the man charged with kidnapping and killing a young Tacoma girl, will plead guilty to murder, officials said on Friday.

Deputy Prosecuting Attorney Mary Robnett said Adhahn is expected to change his plea in a hearing April 7 in Pierce County Superior Court.

Prosecutors have been working with Adhahn's attorneys for some time on striking a plea deal, Robnett said.

Adhahn, a convicted sex offender, previously pleaded not guilty to kidnapping, rape and murder charges in the July killing of 12-year-old Zina Linnik.

Prosecutors have already removed the death penalty as an option as part of a deal to get Adhahn to lead them to Linnik's body after his arrest.

"I have no regrets about taking the death penalty off the table in these circumstances," Pierce County Prosecutor Gerald Horne said at the time. "We may never have found the body."

Adhahn is being held in the Pierce County Jail for Linnik's death as well as in the rapes of two other girls - one of whom survived after apparently being left for dead in a remote section of Fort Lewis.

Zina had been missing since twilight on July 4, when she was snatched from an alley behind her family's home in Tacoma during a neighborhood fireworks display. Investigators said her father saw a gray van leaving the scene, and that his partial recollection of the license plate helped them track down Adhahn at a home south of Tacoma.

He was arrested July 8. Four days later, he rode in a police cruiser and directed investigators to the area near Silver Lake where he had dumped the body, according to charging documents.

Detectives said that as they were investigating Adhahn, they discovered his links to two other victims: an 11-year-old girl who was kidnapped on her way to school, brutally raped and left in a remote part of Fort Lewis in 2000; and another who lived with Adhahn as a teen and said he raped her as many as 200 times. Adhahn is charged with rape and child rape in those cases, as well as failing to register as a sex offender.

He is also a person of interest in the late 2005 abduction and killing of Adre'Anna Jackson, a 10-year-old girl whose remains were found in a Pierce County field last year.

Adhahn came to the U.S. in the 1970s after his mother married a U.S. soldier. He was convicted of incest in 1990 for violently raping a 16-year-old female relative and sentenced to two months in jail, plus five years of counseling. He told his counselors that he had been raped countless times by an older brother while growing up in Thailand, according to a mental evaluation filed in Pierce County Superior Court as part of that case.

His case helped prompt a review of state sex offender laws, and earlier this month Gov. Chris Gregoire signed legislation to increase surveillance of sex offenders.