ST. LOUIS – Prosecutors have charged a St. Louis County police officer with criminal sexual assault in Illinois.

Gavin M. Potthast faces one felony charge in Madison County, Illinois. The St. Louis County Police Department tells FOX 2 that Potthast had been working with the department since December 2021 and was placed on unpaid administrative leave on Friday.

According to court documents obtained by FOX 2, Potthast used or threatened to use force against a 25-year-old victim. Court documents allege the crime happened on Sept. 23, 2023.

St. Louis County Police Colonel Kenneth Gregory released the following statement to FOX 2 in connection with Potthast’s charges:

“We are disturbed by the allegations made regarding our officer’s behavior. We take any allegation seriously and are cooperating fully with the Edwardsville Police Department’s investigation. We are also conducting a thorough internal investigation. The involved officer has been placed on unpaid administrative leave. We hold our staff to a high level of integrity and expect them to treat every member of our community with dignity and respect.”

Potthast is the second St. Louis County officer charged with a crime this month. Prosecutors charged Matthew McCulloch with firing multiple shots into the air during a trunk-or-treat event in Kirkwood. McCulloch is no longer employed by the St. Louis County Police Department.