LA CROSSE, Wis. — A La Crosse police lieutenant has resigned after his arrest on possible drug charges.

Brian Thomson appeared in court Wednesday and is free on a $5,000 signature bond. The La Crosse Tribune reports Thomson was arrested Tuesday and faces possible charges of misconduct and attempted possession of narcotic drugs.

La Crosse police began an investigation into Thomson, and then turned it over to the Wisconsin Department of Justice. Police Chief Ron Tischer says the officer's actions are "unsettling and in direct contrast to the principles embraced by our members."

A special prosecutor will be brought in to avoid conflicts.

Thomson has submitted his resignation. He was a 15-year veteran of the La Crosse Police Department. WXOW-TV reports his attorney declined to comment after Wednesday's hearing.