A school custodian in Vancouver, Washington, was arrested after investigators reported finding 137 videos he had allegedly secretly filmed in restrooms over nearly a decade.

James Mattson, 38, was booked into the Clark County Jail Thursday on suspicion of 137 counts of first-degree voyeurism, The Columbian reported.

The Clark County Sheriff’s Office said he is scheduled to appear on the allegations Friday in Clark County Superior Court. It wasn’t immediately known if Mattson has a lawyer to comment on his behalf.

Vancouver Public Schools said Thursday that Mattson is on unpaid leave, pending termination proceedings.

Mattson has worked for Vancouver Public Schools since 2007 when he started as a substitute custodian and has worked at various schools in the district.

According to court records, a criminal investigation began Oct. 5 after a woman dating Mattson reported finding a video on his computer of a girl changing clothes in a locker room.

Detectives seized several of Mattson’s electronic devices, including computers, while executing search warrants at his Hazel Dell house, according to the Sheriff’s Office.

District officials told the newspaper Wednesday that searches were done of all the locker rooms and restrooms throughout the district and no cameras or active recording devices were found.

Sheriff’s officials said the investigation is ongoing,