Story highlights Michael David Turley is convicted on endangerment and terrorism hoax charges

He posted a video of his nephew with a fake grenade launcher on Phoenix streets

In the video, a man says he and an actor are trying to test police response

Attorney: "This was completely impulsive. He didn't intend to make the police come out."

A man who paraded his cloaked 16-year-old nephew around a busy Phoenix intersection with a fake rocket-propelled grenade launcher was found guilty Monday on endangerment and terrorism hoax charges.

Michael David Turley, 40, posted a video on YouTube last year showing the teen walking around the streets covered in a sheet and pointing the fake weapon at cars. The video went viral with more than 250,000 hits.

In the video, a man says he and an actor are trying to test how police would respond to such a scene at a busy intersection.

Michael Turley

Turley's attorney, Brad Rideout, said the ordeal stemmed from some simple horseplay.

"He was in the house and the nephew put on the sheet and started fooling around," Rideout said. "He took his still camera and started taking photos. He put up the video like he was testing the police department, but he really wasn't. This was completely impulsive. He didn't intend to make the police come out. He didn't intend to make it look like a terrorist act."

When asked if he thought 911 callers were actually scared, the attorney responded, "If someone comes to your front door with a samurai sword on Halloween, you would still be scared even though it is Halloween."

Turley faces up to five years in prison. Sentencing is set for August 8.