Story highlights Kendra Gill and 3 other 18-year-olds accused of making, throwing explosive devices

Devices had potential to maim or kill, Fire Authority captain says

One teen told investigators that they were "pranking," probable cause document says

A teen beauty queen in Utah and three others were arrested Saturday morning for allegedly making and throwing bombs that an explosives investigator says could have killed someone.

Kendra Gill, Bryce Stone, Shanna Smith and John Reagh -- all 18 -- admitted to buying the materials for the explosives, making the devices and throwing them from a vehicle, according to a Salt Lake County Sheriff's Office probable cause statement that CNN obtained.

Gill was crowned Miss Riverton in June, and was set to compete for the Miss Utah title, CNN affiliate KUTV reported

Investigators began getting calls late Friday night from Riverton residents who heard "loud pops," said Capt. Clint Mecham of the Unified Fire Authority which is investigating the case.

"The adults who were arrested were driving around in a car throwing these devices at property and people," Mecham said.

Photos: Teens arrested in bomb-throwing case Photos: Teens arrested in bomb-throwing case Teens arrested in bomb-throwing case – Kendra Gill, who was crowned Miss Riverton in June, and three others are alleged to have thrown explosive devices. Hide Caption 1 of 4 Photos: Teens arrested in bomb-throwing case Teens arrested in bomb-throwing case – John Reagh was among four teens arrested in the alleged bomb throwing case. Hide Caption 2 of 4 Photos: Teens arrested in bomb-throwing case Teens arrested in bomb-throwing case – Shanna Smith, 18, was among four teens arrested in the bomb throwing case. Hide Caption 3 of 4 Photos: Teens arrested in bomb-throwing case Teens arrested in bomb-throwing case – Bryce Stone allegedly implicated the three other teens arrested over the weekend in the case. Hide Caption 4 of 4

Authorities found plastic bottles that contained household cleaning chemicals and aluminum foil strewn in streets around the community, he said.

"Not only do you have to worry about shrapnel, these type of devices have chemicals" that can cause burns, Mecham said.

"This is not your average kid blowing up a mailbox," he said. "These devices, they have the power to create a fair amount of damage. They can maim or kill a person."

The teenagers allegedly throwing the devices could have been badly hurt, too, he said.

"They could have lost their lives, fingers, hands," Mecham said. "It's not a very smart thing to do all around."

Authorities interviewed witnesses in two parts of town who described seeing a similar dark-colored vehicle whose occupants were throwing explosive devices, according to a probable cause statement. One of the witnesses identified Stone as the driver and gave investigators his address.

Authorities went there and questioned Stone, who allegedly implicated the three other teens, saying they had been "pranking" with fireworks with friends, the probable cause document says.

Stone allowed authorities to search his car, where remnants of water bottles with labels and sizes matching debris at the bombing scenes were recovered, according to the document. A roll of aluminum foil, toilet bowl cleaner and several water bottles containing multiple pieces of rolled-up aluminum foil were also found, the document says.

Gill, Stone, Smith and Reagh were taken into custody for questioning, and they admitted to buying, making and throwing the explosives, according to the document.

The teens were booked into the Salt Lake County Jail on 10 counts each of setting off an incendiary device, Mecham said.

All the teens bonded out Sunday night for $50,000 each, said Cammie Scogg, a Salt Lake County sheriff's spokeswoman.

Salt Lake County District Attorney Sam Gill told CNN on Monday that his office is waiting for a full report from authorities to decide on whether to file charges.