A former office staff employee at Kent-Meridian High School pleaded not guilty to third-degree child rape for allegedly having a sexual relationship with a 15-year-old male student.

Kristal M. Gamble, 33, of Olympia, entered the plea Thursday in King County Superior Court at the Maleng Regional Justice Center in Kent. She is scheduled to return to court Dec. 12, but those court dates are often continued numerous times as attorneys prepare the case.

Kent Police arrested Gamble Nov. 15 for investigation of rape. She was booked into the county jail and posted bail on Nov. 16. Bail was set at $10,000.

Gamble initiated an inappropriate relationship with the victim that began with text messages and escalated into a sexual assault, according to charging papers. Facebook and text messages between Gamble and the student occurred from April through August of this year, according to time stamps.

The boy’s parents found sexual photos and messages on their son’s cellphone, then contacted Kent Police in September, according to court documents. By then, Gamble was no longer working at Kent-Meridian, according to the Kent School District.

Explicit communication between Gamble and the student occurred during school days, the incident report said. The boy said initial exchanges pertained to school and her wanting to be his mentor. However, he said, a lot of flirting began and that she wanted to have sex with him, the incident report said.

Gamble, according to the incident report, made a deal with the student, telling him that if had good attendance at school, she would have sex with him. The woman met the student at a water park near the high school, where she gave the boy oral sex, according to charging papers.