FORT COLLINS, Colo. (CBS4) – Five times now a vehicle’s window has been shattered while traveling in Northern Colorado. The latest happened Tuesday morning on Interstate 25 in Fort Collins.

A driver remains hospitalized after a bullet came through her window last week. There are also cases under investigation in Loveland, Mead and Keenesburg. The struggle now is trying to find a common link in the cases.

RELATED: Woman Shot While Driving On I-25: ‘I Don’t Understand, But I’m Trying’

State troopers and deputies on Tuesday inspected the pickup truck involved and didn’t find any bullet holes, or bullets lodged. That leaves the shattered glass scare, like most of the others, a mystery.

“Glass just shattered and just went all over,” said Randy Lingbloom from Cheyenne, Wyoming.

Randy Lingbloom's shattered window (credit: CBS)

Randy Lingbloom’s shattered window (credit: CBS)

He wasn’t hurt. He was in the left lane driving southbound from Cheyenne to Lafayette when his window shattered as he passed the Budweiser plant in Fort Collins.

Nobody seems to know what caused the window to break. So far authorities have only been able to explain one of the bizarre incidents. Last Wednesday someone shot out Cori Romero’s car window as she entered the highway near Fort Collins, seriously injuring the 20-year-old.

(credit: CBS)

(credit: CBS)

Romero had called 911 because she thought she had been in a crash near Fort Collins before realizing someone actually shot a bullet through her sedan window, striking her in the neck.

Cori Romero gives a thumbs up from her hospital room after being shot in the neck (credit: Lesley Quezada)

Cori Romero gives a thumbs up from her hospital room after being shot in the neck (credit: Lesley Quezada)

Knowing what happened to Romero, and of the other broken windows reported recently, Lingbloom called 911 right away.

“First thing that hit my mind is what these other people are going through,” Lingbloom said. “I knew this has been happening around this area, and I drive up and down here all the time. It’s just something that you hear about, but you don’t think is going to happen to you, you know.”

Randy Lingbloom's shattered window (credit: CBS)

Randy Lingbloom’s shattered window (credit: CBS)

In nearly all the cases the driver’s side front or back window shattered.

Deputies still have no leads in last week’s shooting, and there’s still a possibility at least some of the broken windows are just a coincidence. But since authorities can’t prove they aren’t shootings, drivers — especially along I-25 — are on alert, and on edge.