Surveillance video was collected from neighboring properties.
"There's all kinds of crazy stuff out there, but a pipe bomb?" one neighbor said. "For somebody to put it together and bring it into your neighborhood? That's scary."
Pima County Sheriff's Deputy John Morris is on the Pima Regional Bomb Squad. He explained these kinds of incidents don't happen often, but when they do, they're taken extremely seriously.
"Dependent on the materials that are being used as well, they are very dangerous and deadly," he said. "Anybody could wind up making these things. There are very small steps to make these things very powerful and dangerous."
Investigators are asking for help to identify those responsible for the explosion.
Morris wants the public to know that if something seems off, if they notice something very out of place, it's best to report it to the authorities.
If you have any information call 9-1-1 or 88-CRIME. You may remain anonymous.