(DENVER) — Alexa Bartell spoke to a friend over the phone while driving Wednesday night near Denver when the line suddenly dropped.

Concerned about Bartell’s well-being, her friend eventually tracked Bartell’s phone to a field in Jefferson County, Colorado, where she found a damaged yellow Chevy Spark. According to the Jefferson County Sheriff’s Office, a large rock had broken through the car’s windshield, striking and killing the 20-year-old Bartell — one of at least five similar incidents in Colorado over three hours on Wednesday evening.

“This is the most tragic of a series of similar crimes that happened overnight throughout Jefferson and Boulder counties,” the press release noted about the homicide.

The Jefferson County Sheriff’s Office has been unable to identify any suspects associated with the crime spree, including the homicide. Investigators also believe there may have been more than five incidents and have asked victims to come forward.

Law enforcement initially believed the incidents were associated with a 2003-2005 Dodge Ram pickup truck and asked the public to help identify its owners. However, investigators later confirmed the owner of the car was not “involved in the crime series related to the death of Alexa Bartell,” leaving no suspects.

“[Jefferson County Sheriff’s Office] continues to urge anyone with information about the crime to call our tip line at 303-271-5612,” the press release read.

Based on a timeline released by the sheriff’s office, the incidents began around 10 p.m. Wednesday when the suspect or suspects threw a rock through a car’s windshield in Westminster, CO. The driver was uninjured by the incident.

Thirty minutes later and roughly ten miles away, another rock was thrown through a windshield, injuring the driver. A minute later, at the same location, the suspects threw a rock at Toyota SUV, damaging the vehicle’s body but leaving the driver unscathed.

The event that resulted in Bartell’s death was the fourth such recorded incident Wednesday evening. At 10:45 p.m., Bartell was driving down Indiana Street in Jefferson County, CO, when a large rock broke her windshield and fatally wounded her.

Nearly two hours after striking Bartell’s car, the suspects allegedly struck their final car of the evening in Arvada, CO – more than 25 miles from the scene of the fatal incident. The last incident injured the car’s driver.

“We believe there may be more victims,” the sheriff’s office’s release noted, urging the public to come forward if they have any information or dash camera video from the evening that might offer insights into the deadly incident. With incidents crossing multiple counties in the Denver metropolitan area, the Jefferson County Sheriff’s Office is working with the Boulder County Sheriff’s Office, Arvada Police, and Westminster Police.

As of Thursday evening, the Sheriff’s office has been unable to identify any new suspects.

Copyright © 2023, ABC Audio. All rights reserved.