Crystal Lake South coach Jay Mueller talks with the Gators during their girls soccer IHSA Class 2A sectional semifinal at Rochelle High School on Tuesday, May 22, 2018 in Rochelle. Crystal Lake South won 3-2 in overtime.

A Crystal Lake South teacher and coach was placed on paid administrative leave on Tuesday in what Community High School District 155 describes as an ongoing personnel matter involving a minor, according to communication from the district.

The Crystal Lake Police Department notified District 155 that it was initiating an investigation into Jay Mueller, head girls soccer coach and chemistry teacher at Crystal Lake South, on Tuesday morning.