Minneapolis police are investigating a hole apparently made by a pellet shot in the window of Sen. Al Franken's downtown condominium.

Police spokesman Sgt. Bill Palmer said Wednesday that Franken and his wife, Franni, recently found the hole upon returning to their condo after a few days away. Palmer says the hole appeared to have been made by a pellet.

Palmer says police don't know if the Franken residence was purposely targeted and "don't have much to go on."

Franken's office reported the incident to the U.S. Capitol Police, which spokesman Marc Kimball says is a standard move for members of Congress. Kimball wouldn't say whether the office had received any prior threats.