Police in Los Angeles say that the dry ice bombs found in supposedly secure areas of Los Angeles International Airport earlier this week may have been set by a disgruntled employee, though the exact reason for placing the devices is still unclear.

The police also clarified that only one of the bombs — the first one to be discovered — had exploded. None of the other devices, all of which consisted of dry ice placed in 20-ounce plastic beverage bottles, located afterward were set off.

Though the first device, discovered in a bathroom inside Terminal 2 on Sunday night, luckily did no damage to property or people, police say the bombs could have resulted in serious injury if anyone had been nearby during the explosion.

According to the AP, police have not identified a specific suspect but believe that the bombs may be related to a labor dispute at the airport. The L.A. Times says police are still leaving open the possibility that this is just a really bad prank.

Police say they are are not currently treating this incident as an act of terrorism, but the FBI is assisting in the investigation.

“The focus is definitely in the restricted area, not in the areas where passengers have access,” said airport police sergeant earlier today. “We want to make sure that that gets tightened up.”

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.