CLEVELAND (WJW) – The FOX 8 I-Team has uncovered a local highway mystery after an off-duty police officer called 911 to say the back window of her SUV suddenly shattered.

She suspected the window had been shot out, but investigators still are not sure what actually happened.

Last week, near midnight on Friday, an off-duty Berea police officer was driving on the Jennings Freeway in Cleveland. Suddenly, she said it sounded as if someone had shot out her rear window.

She told a 911 dispatcher, “Somebody either threw something from the road past my vehicle or shot my rear window out of my vehicle.”

She kept driving down the highway, telling the dispatcher, “I wanted to make sure the vehicle that shot me, I wanted to make sure I got away from them. I don’t know if they shot me or what’s going on.”

Ultimately, she stopped in Brooklyn Heights. Officers there scrambled to make sure she was OK and take a look at what happened.

She told Brooklyn Heights police, “When it happened, it just immediately shattered my windshield. I’m like, ‘Oh my God, what happened?'”

An officer asked, “Are you OK?”

The driver answered, “Yeah, just like, freaking. Like, what in the —“

Cleveland police have investigated, but they’re not sure why the window shattered. A police report shows the driver “confident it was a gunshot she heard,” but she said there had been no road rage incident with anyone.

Officers searched, but they could not find any evidence of a bullet fragment.

A couple of officers told us police have also wondered if something as simple as the cold weather had something to do with that window suddenly shattering. It’s odd, but one veteran, local body shop owner told us that he’s seen rear windows shatter because of a short or a problem with the rear window defroster.

The off-duty officer told us she couldn’t comment without permission from her department and with the case still under investigation.

We’ve also contacted the National Highway Traffic Safety Administration. The agency is now doing some research looking for any similar cases or possible explanations.

For now, what happened remains a mystery.

The driver added while talking to police at the scene, “It took out, like whatever, this bottom edging of the glass. It pretty much exploded.”

Police did not have reports of any other shots fired into cars in that area.