Mystic — A bomb threat forced the evacuation of Mystic Aquarium for two hours Monday afternoon.

Stonington Police Capt. Todd Olson said a janitor discovered a written message in a bathroom and police were notified at 2:34 p.m. Olson declined to discuss the content of the message.

Aquarium staff members and visitors were evacuated, the Mystic and Old Mystic fire departments responded and three state police bomb-sniffing dogs arrived and searched the entire facility, Olson said.

Nothing suspicious was found and people were eventually let back inside. The incident remains under investigation.