Three Colorado teens have been arrested  for a string of rock-throwing incidents on Jefferson and Boulder County streets and highways — including one that killed a 20-year-old driver.

Alexa Bartell was on the phone with a friend at about 10:45 p.m. Wednesday night when her phone suddenly went dead, as CrimeOnline previously reported. The friend was able to track Bartell’s phone, locating her vehicle in a field. She died from her injuries.

The Jefferson County Sheriff’s Office announced the arrests of Joseph Koenig, Nicholas “Mitch” Karol-Chik, and and Zachary Kwak Wednesday morning, KMGH reported. All three are 18 and from Arvada, which was also Bartell’s home.

The three face charges of first degree murder and extreme indifference, the sheriff’s office said, adding that more charges are expected.

“While it remains unclear at this time which suspect(s) were driving throughout the spree, the suspect vehicle is a black 2016 Chevy Silverado,” the sheriff’s office said, according to KKTV.

At least seven incidents of rock-throwing that night have been reported in the area, investigators said. The sheriff’s office previously said the rocks were four to six inches long and three to five pounds, “essentially used as a deadly weapon.”

Drivers suffered minor injuries in two of the other incidents. Bartell’s vehicle was the last one known to have been struck in the rock-throwing, KMGH said. All the incidents took place between 10 p.m. and 10:45, when Bartell was hit.

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[Feature Photo: Alexa Bartell/Jefferson County Sheriff’s Office]