COTTONWOOD HEIGHTS, Utah - Cottonwood Heights Police are trying to track down an assault rifle stolen from a well-known gun lobbyist.

Clark Aposhian is the chairman of the Utah Shooting Sports Council. He teaches a gun safety course and is at the forefront of issues regarding the second amendment.

On Thursday night, Aposhian's AR-15 assault rifle was stolen from his locked car. The vehicle was parked in the driveway of his Cottonwood Heights home.

"It's pretty shocking, this is a guy whose livelihood is built teaching conceal and carry permit classes and gun safety," said Maryanne Martindale, executive director of Alliance for a Better Utah.

ABU is a non-profit progressive group that opposed Aposhian's support for House Bill 76, the law that would've allowed gun owners to carry their conceal guns without a permit. Governor Herbert vetoed the law.

"I would view Clark prior to this incident as someone with a heightened awareness of gun safety and gun protocol," said Martindale. "He's someone who's always talking about what people do and this is how people carry them and take care of their weapons. I'm a gun owner, I know where my gun is, it's got a trigger lock, it's unloaded and in a lock box in my house."

When asked if she's ever left it in her car, Martindale replied, "absolutely not."

FOX 13’s Gene Kennedy talked with Aposhian several times on Thursday. He said he was cleaning out his garage and that's why his Dodge Magnum station wagon was in the driveway.

The rifle, which is worth thousands of dollars, was in a locked soft case in the trunk area. Beyond that, Aposhian wouldn’t make statements on-camera.

"To leave a weapon of that value, an assault rifle, in a car is just nuts," said Sgt. Scott Peck of the Cottonwood Heights Police Dept.

What police fear is that the weapon may soon be on the streets.

"We definitely have a concern," said Sgt. Peck. "There's lots of them everywhere and we know there's another one out there and it's in the hands of a thief obviously."

"My second thought after my surprise and shock at this is 'Great!' now there's someone out there with a stolen AR-15. What are they doing with it, what's the plan," asked Martindale.

Aposhian told FOX 13 the gun wasn’t loaded but police aren't sure.

Cops say, fortunately, it is registered. They're hoping to use a serial number to help track it.