A substitute teacher in Maryland accused of inappropriately touching a student has worked in 43 schools over the past two years, district officials said.

Steven Katz, 59, of Columbia, was charged Saturday with sexual abuse of a minor and a fourth-degree sexual offense after a student at Clovery Elementary School told his parents that Katz — while working as a substitute teacher on March 8 — had touched him in a way that made him uncomfortable, according to Montgomery County police.

Michael Martirano, interim superintendent for Howard County Public Schools, told reporters Monday that Katz had worked in the district for six years and may have taught at other schools, according to the Baltimore Sun. Officials were in the process of reviewing his complete employment history, Martirano said.

“Understand very clearly that when it comes to the safety of our young people that I take very serious, and that we’re doing everything that we can, every day, to protect our young people,” Martirano said. “If somebody is in our school system – a staff member, a volunteer, or anyone – causing harm to our children, I will take swift and decisive action to ensure that that never happens again.”

Martirano said district officials have not received complaints in connection to Katz in Howard County. In a letter sent to parents on Sunday, Martirano said Katz’s arrest “came as a surprise” and listed 43 schools where he previously taught as a substitute. An improved process to evaluate substitutes, including more frequent background checks, has also been launched, he said.

“My office and our school leaders have been asked why this individual was able to work as a substitute teacher during the time he was being investigated by the Montgomery County Police Department,” Martirano wrote. “Unfortunately, news of the arrest came as a surprise to us as we were not aware that this individual was suspected of these charges until Saturday, March 17. This put us in a position of responding to a situation without have many details.”

Katz “made admissions” relating to inappropriately touching the male student, according to Montgomery County detectives, who said parents who suspect their child may have had an inappropriate encounter with Katz should contact police at (240) 773-5400.

Katz remains free after posting $10,000 bail, WBAL reports. It’s unclear if he’s hired an attorney.