SEATTLE -- A woman who exposed a middle school teacher’s child pornography habit said she has been hiding since last May because she feared the consequences from the teacher and his supporters, reported KIRO 7 Eyewitness News.

In an exclusive interview with KIRO 7 Monday, Sharyn Thoma-Guay explained how she told police about her boyfriend’s collection of child pornography nearly a year ago.

Her boyfriend, Tim Sheehan, was a popular video-production teacher at Whitman Middle School in Ballard. Thoma-Guay said Sheehan talked about fantasies of having sex with and killing young boys and showed her numerous images of child pornography on a laptop computer he used at the school.

Thoma-Guay said she was terrified that Sheehan’s students would become his victims but said Sheehan physically intimidated her and she knew the teacher's supporters would make her a target of public ridicule.

“I was afraid that I would go and tell them (the police) this, and he (Sheehan) would get rid of everything and they would find nothing, and that he would still be teaching. And the only person that would know would be me,” said Thoma-Guay.

Thoma-Guay told police about Sheehan’s activities last May and authorities found the images Thoma-Guay had described during a search of Sheehan’s home.

According to a Seattle police document, Sheehan apparently used his job to fuel his fantasies.

"Sheehan told Thoma-Guay that he liked when the children did interviews because it got head shots of his students. Whereas he used to have to look on the net for photos of children, he now enjoyed the fact that he got to ‘Watch them in slow motion, frame by frame,’” a court document said.

Sheehan pleaded guilty to child porn charges last week and resigned from his teaching job.

“I just wanted people to know only one thing, and that’s that I only did this for the kids,” said Thoma-Guay. Now I feel like I can move on because I did a good thing. It cost me, but I know it was worth it.”

Until this week, Sheehan continued to be paid by Seattle Public Schools despite being suspended from work.

Sheehan will be required to register as a sex offender.