LINCOLN, Calif. (KTXL) — Placer County Sheriff’s Office deputies announced on Monday they arrested a 25-year-old from Lincoln on suspicion of possessing child pornography. 

The sheriff’s office identified him as Zachery Wilkendorf, an instructor at Lincoln Family Taekwondo Academy.

William Wong, the gym owner, told FOX40 he fired Wilkendorf immediately after finding out about his arrest.

“He just was a friendly guy, upfront, but apparently he had other stuff going on,” James Mann Jr., a student, said

Mann Jr. and his father began taking lessons under Wilkendorf and other instructors in February. Mann Sr. said he even signed his 4-year-old grandson up to learn.

“It just hurts; it hurts. You’ve got somebody that you respect and trust and to find out this kind of stuff, especially with kids of all things. It’s devastating,” Mann Sr. said.

According to the sheriff’s office, Wilkendorf was arrested on suspicion of possessing “numerous child pornography content.” The post says investigators worry there may be other unidentified victims “based on Wilkendorf’s access to children and the children pornography in his possession.”

“I didn’t even know he would be into stuff like that honestly. I’m still at a loss for words, honestly, I just don’t know what to say,” Mann Jr. said.

Mann Jr. said he picked up taekwondo quickly under Wilkendorf’s tutelage and his father even considered the instructor a friend.

“This is somebody that, if I wasn’t there, I’d feel comfortable dropping my grandson off and go run an errand real quick and come right back,” Mann Sr. said.

He said he is now thankful he never left his grandson there alone with Wilkendorf. But now he’s left wondering if there were any signs he and his son may have missed.

“In hindsight, watching him interact with my grandson and son, I didn’t see anything weird and that’s scary,” Mann Sr. said. 

Mann Sr. said Wong – the owner of the gym – called all the families afterward to make sure they were OK and had no incidents with Wilkendorf.

His son said Wilkendorf never gave off any red flags during their training.