Authorities were offering a reward for information and seeking surveillance videos Friday after someone apparently threw rocks at multiple windshields of passing cars in suburban Denver earlier this week, killing a young woman.

Police said Alexa Bartell, 20, was driving and talking on the phone with a friend around 10:45 p.m. local time Wednesday when she suddenly went silent. Her friend tracked her phone and discovered Bartell’s body in her car, which had run off the side of the road.

Police don’t have any suspects but were searching for a light-colored pickup or SUV and were offering a $2,000 reward for information.

The Jefferson County Sheriff’s Office said in a news release that Bartell’s death appears to be connected to a string of incidents in the area around the same time,

Tennessee:Five children, young adult killed after car collides with vehicle, rolls over in Tennessee

Maryland: Six construction workers killed after car veers into highway work zone, Maryland police say

Who threw the rock?

Investigators initially believed the killing was part of an “overnight crime series involving a light-colored pickup truck or SUV.” A map released by the sheriff’s office shows the incidents all happened within a few miles of each other, and took place over about 45 minutes.

Authorities said the suspects or suspects were involved in at least five incidents, including the attack that killed Bartell. In four incidents, a rock went through a vehicle’s windshield. In the fifth, police said, the vehicle received body damage.

“Investigators need the public’s help identifying in locating the suspects involved in these crimes,” Metro Denver Crimes Stoppers said in a plea for help. “No piece of information is insignificant. If you have home security or dash cameras that may have caught the vehicle driving by, we want to hear from you.”

The sheriff’s office specifically asked for Tesla owners to check their vehicles for footage, as those vehicles have multiple cameras and record while driving.

The sheriff’s office posted a series of updates on Facebook regarding the light-colored truck investigators were looking for.

Investigators on Thursday tracked down one vehicle seen in the area and concluded it was not connected to the rock-throwing attacks.