DURHAM – No injury or damage was reported Tuesday when a water bottle filled with an unidentified liquid chemical apparently exploded in a rural mailbox at 49 Cedar Pond Road.

The exploded bottle was discovered by a mail carrier around 11 a.m. Durham Fire Department personnel stood by until Androscoggin County Sheriff’s Sgt. Jim Jacques arrived.

Jacques concluded it was probably a prank, but the bottle apparently exploded inside the box sometime before it was opened without causing any damage.

The incident remains under investigation, Jacques said.

Fire Chief Bill St. Michel said there had been a couple of mailbox incidents over the years and warned, “If this was intended as a prank, it’s a very dangerous prank. Somebody could get hurt, either the individual placing it in the box or an innocent person.”

According to a spokesman for the U.S. Postal Service District of Maine, the incident is being referred to the U.S. Postal Investigation Service, the law enforcement arm of the USPS. Interfering with the delivery of mail or destroying mail in a box is a federal offense.