Updated

A Utah beauty pageant winner and three other 18-year-olds have been arrested on suspicion of throwing crudely-made bombs at ten homes.

Unified Fire Authority Capt. Clint Mecham said authorities began receiving calls late Friday of people throwing explosives out of a vehicle around Riverton, the Salt Lake Tribune reports.

Arson investigators looked at the scene of one such incident and found four plastic water bottles with pieces of aluminum foil and a chemical substance that was detonated on roads near a home.

“All of us were surprised when we not only had one occurrence, but up to 10 occurrences of this happening,” Mecham told Fox 13 News. “They were actually throwing these at people with the intent to cause harm, with the intent to cause harm to either people or property: This goes well beyond a teenage prank.”

A witness tipped off police about the four suspects: Kendra McKenzie Gill, the 2013 Miss Riverton pageant winner, John Reagh, Shanna Smith and Bryce Stone.

The four reportedly confessed to the incidents and police said they bought the bomb materials at a Walmart, according to Fox 13 News, but no motive has been revealed.

Stone told police that the group was “pranking” with fireworks, and a search of his vehicle’s trunk uncovered remnants of a case of water bottles matching the ones that were exploded, aluminum foil and toilet bowl cleaner, jail records say.

No one was hurt by the bombs. Each suspect was booked into the Salt Lake County Jail Saturday morning but released later in the day after posting bail. They were each charged with setting off an incendiary device and could face felony charges, Fox 13 News reports.

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