SAN MATEO -- A 20-year-old San Mateo-Foster City School District employee who works at an after-school child-care program was arrested for kissing and groping an elementary-age student, police said Wednesday.

Officers took Eric Michael Renz into custody at his Millbrae home Friday on suspicion of lewd acts on a girl he befriended at Horrall Elementary School on Ocean Avenue. Investigators haven't found any other victims so far, but were continuing their investigation, San Mateo police Sgt. Ryan Monaghan said.

Renz, a part-time district employee, is on paid administrative leave while the police investigation continues. A man who answered a phone number registered to the Renz family Wednesday told a reporter not to call back and hung up.

A district worker saw the victim sitting on the suspect's lap on Oct. 18, a Friday, and believing it to be inappropriate reported it to administrators late that night, Assistant Superintendent Molly Barton said. The district was initially going to "get to the bottom of what happened," but over the weekend decided to call police. Renz was not working with students that weekend.

District officials notified police and Child Protective Services on the following Monday and placed Renz on leave. State law requires educators to immediately report suspected abuse directly to police.

The San Mateo police investigation that began Oct. 21 led to Renz being booked into San Mateo County jail on suspicion of lewd acts on a child under 14 and annoying a child, Sgt. Dave Norris said.

Renz is out of jail on $100,000 bail and is due in San Mateo County Superior Court on Dec. 5, if charged with a crime, Chief Deputy District Attorney Karen Guidotti said.

People with information about this incident or other possible victims can call San Mateo police at 650-522-7650.

Contact Joshua Melvin at 650-348-4335. Follow him at Twitter.com/melvinreport.