He said by the time arson investigators caught up with the suspects, a total of nine incidents were reported.
According to a probable cause statement released by the jail, the first report arrived about 10:50 p.m. Friday. When authorities arrived, they found four plastic water bottles with remnants of aluminum foil and a chemical substance that had been detonated in a driveway and roadway near a residence.
Witnesses stated that a dark-colored, gray or black passenger car with a dent on the front of the vehicle was seen driving by the house and someone inside threw four bombs at a house, which caused loud explosions, jail records indicate.
Unified police then received reports of more explosions in the area of 13800 S. 4100 West. A similar vehicle was seen in the area and occupants inside threw bombs at several individuals. The police report indicated one bomb was thrown at Stone's ex-girlfriend's house.
Witnesses from the scene told police that Stone drove a similar vehicle.
Police and fire investigators located the vehicle in front of what the witness said was Stone's residence.
Stone told police he and friends had been "pranking" with fireworks, according to jail records. Stone was arrested and allegedly implicated Gill, Smith and Reagh.
When police searched Stone's trunk, they said they found remnants of a case of water bottles with labels and sizes matching the debris at the scenes of the explosions; a roll of aluminum foil; and toilet bowl cleaner.
Several of the bottles had been emptied of water and contained rolled up aluminum foil.
Investigators said all four were arrested and admitted to buying the supplies, making the devices and throwing them out of the window at two addresses in Riverton.
The jail records do not indicate the explosions caused any damage. Mecham said no one was injured, but said the use of explosive devices are taken seriously and, in some cases, could be classified as a type of terrorism.
"Anytime you're dealing with explosives and incendiary devices, those are always felony charges," Mecham said. "The fact that there are multiple [detonations] of them, makes this extremely serious."