Police are up in arms over an iPhone case that's shaped like a gun.

"Most kids carry their cell phone in their back pocket, and if someone reaches for it, in my mind they're reaching for a gun," said Al Della Fave, a retired New Jersey state trooper and firearms instructor.

Dellla Fave, a spokesman for the Ocean County Prosecutor's Office in New Jersey, shared a Facebook (FB) photo of the iPhone case that he found on a closed social media site for cops. A model poses with her phone tucked into her back pocket, and the protruding case looks like the handle of a semiautomatic compact pistol.

Della Fave said that if a teenager draws the phone in the presence of a cop "the first thing they're going to see as it's coming up is the trigger guard and the butt of the gun. This doesn't seem like a good idea at all to me."

The model in the Facebook image also poses with the phone next to her face, talking into it, and it looks like she's brandishing a gun.

The phone case is sold online by various retailers at prices from about $5 to $49 and comes in several different colors.

"The app means you can play games of Russian Roulette at parties!" said Japan Trend Shop, in its online product description. "Don't worry, you can't actually shoot anyone!"

The NYPD did not return messages from CNNMoney. But an NYPD cop from the 112th precinct of Queens, NY, tweeted the image with a few words of advice, "I would NOT suggest purchasing this cell phone case, which was designed to look like a firearm."

It is not clear who manufactures the case.

"If it's on the web then it's out there somewhere, that's the bottom line," said Della Fave.