Denniro/ThinkStock

A St. Louis-area sheriff's department has apologized after a deputy used mud to cover a private home's outdoor surveillance camera.

The Jefferson County Sheriff's Department posted the apology Wednesday night on Facebook and said an internal investigation is under way.

Department spokesman Grant Bissell told the St. Louis Post-Dispatch that the investigation is looking to determine the deputy's motivation for smearing the camera with mud on Sunday. Authorities have not said if the deputy has been disciplined.

Bissell says deputies went to a home near Imperial after St. Louis County police asked them to help find a registered sex offender who failed to check in with authorities monitoring the state's registry. Deputies did not find the man at the home.

The woman who owns the home says she is infuriated.