Authorities in a Colorado town are investigating after an explosive device was left in front of the local police department. Paul Carrill of the Nederland Police Department said a detective discovered a backpack in front of the building before starting his shift on Tuesday, the AP reported on Wednesday. After bringing the bag inside, the detective found what looked like a homemade explosive device. Two robots searched the bag and parts of the improvised device were removed and sent for forensic testing. Details on the possible motive have not been released, nor have details on possible suspects.