CHICAGO (CBS) — He’s been a trusted Chicago Public Schools educator for two decades.

But now a dean at Foreman High School is under investigation for a past child abuse conviction and claims of sexual abuse.

CBS 2’s Dana Kozlov talked to one victim, who says he couldn’t stay silent any longer.

Ron Tremp shares a photo taken in 1978, around the time he says Chicago high school dean Jerry Mash molested him.

“He took advantage of my innocence, and I’ll never forgive that man for what he did to me,” Tremp says.

Tremp, who is now nearly 50, says the Penn State/Jerry Sandusky case finally prompted him to track down his alleged abuser.

He found him, serving as the dean of attendance at Foreman High School.

“I was angry and outraged. I was concerned that he was molesting other kids,” Tremp says.

He and another alleged victim have now filed a lawsuit against Mash, charging him with repeatedly molesting them in the 1970s. What’s equally disturbing to Tremp, though, is Mash had previously been convicted of child abuse in 1976 — abuse his victim characterized as sexual.

Even so, less than 15 years his conviction, CPS hired Mash to teach children.

“We hope they will do all they can, now, to first of all, remove Mr. Mash from his position; secondly, to reach out to anyone else who may have been hurt and to diligently ensure that he doesn’t have any access to any more children,” says Barbara Blaine, president of SNAP.

Thursday, a CPS spokesperson said when they learn of a situation like this, “We immediately take steps to remove the individual from contact with students while conducting a thorough investigation, which is what we’ve done in this case.”

CBS 2 tried to reach out to Mash but was unsuccessful.

Tremp did file a police report back in 1978 but says — out of fear of being ridiculed — he and his mother never went forward with the case.

CPS said a 1990 background check of Mash did not turn anything up.