An 18-year-old high school senior was arrested Tuesday after a cleaning lady found a device that was later determined to be an improvised explosive device, Tempe Police said.
About 2:30 p.m. Tuesday, the housekeeper found a strange device with wires coming out of it while going about her regular cleaning duties.
She took the device to a Tempe fire station to be checked out, and also reported she had seen other suspicious materials at the residence.
When firefighters saw the device, they contacted Tempe Police's bomb squad. Bomb investigators came out and confirmed the device was a legitimate IED.
"They had it X-rayed, they saw it was a valid IED. It was something that wasn't big, but could cause serious injuries and the death of someone," said Tempe Police Sgt. Mike Pooley.
They disabled the device and detectives responded to search the home, located in the 1600 block of E. Candlestick Road. There, they found materials used for making improvised explosives, according to police.
They arrested Joshua Prater, an 18-year-old student at Marcos de Niza High School.
He was booked on charges of misconduct involving weapons and possessing a prohibited weapon.
According to a police report, Prater admitted to building the IED, but said he made it about eight years ago and didn't know it was filled with explosive powder.
The IED was made out of an empty CO2 cartridge, hobby fuse and was filled with a low explosive powder, match heads and fireworks. It meets the definition of an improvised explosive device, as defined under "misconduct involving weapons."
It isn't clear what Prater intended on doing with the device.
The cleaning lady put herself in danger when she transported the device to the fire station, but police say she may have saved lives by coming forward.
"She did the right thing. This a very dangerous device that could have killed somebody."
Prater's parents apparently told police he learned how to make the bomb from his friends. Prater's next court date is May 15.
The investigation is ongoing.