A 16-year-old student was arrested after the explosive device was found at Centaurus High School Monday morning.
Lafayette Police Cmdr. Gene McCausey says the device that was similar to a pipe bomb forced the evacuation of the school and the closure of a nearby road for several hours.
McCausey says the device could have hurt people nearby had it exploded.
The FBI and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives are involved in the investigation.