Investigators are trying to determine if a shooting on a major highway in Colorado that left a 20-year-old woman wounded is related to three similar incidents in the area.

Authorities said the attack on Wednesday night came a day after a sheriff's van transporting prisoners was hit by a projectile on Interstate 25 about 20 miles away, shattering a passenger window.

On Thursday, a driver in Weld County said his front driver's side window had been broken and might have been shot out near Interstate 76. Another man said his rear window was shattered Wednesday in Loveland.

No injuries were reported in those three incidents.

The woman was shot in the neck on Interstate 25 about 60 miles north of Denver. Her name and condition were not released.

The sheriff's office says it does not appear she was specifically targeted by the shooter, the Fort Collins Coloradoan (http://tinyurl.com/ns2u3ow ) reported.

Larimer County Sheriff Justin Smith said drivers should be aware and report suspicious behavior as deputies investigate.

"There's a lot more leg work that needs to be done on this case," Smith said. "It's hard because at this point we have no indication that this person was targeted by a person looking for her."

He said people should be aware of the incidents but not overreact.