From left, Zachary Kwak, Nicholas Karol-Chik and Joseph Koenig
CNN  — 

Three teens were arrested in the death of a 20-year-old Colorado woman who was killed when a large rock thrown at her car went through the windshield, the Jefferson County Sheriff’s Office said in a news release Wednesday.

Alexa Bartell was killed April 19 after a series of cars were hit by rocks that night, Jacki Kelley, public information officer with the sheriff’s office, said in a news conference Wednesday. Authorities believe at least seven people were hit by the rocks.

Investigators arrested the three teens in connection with her death Tuesday night, the sheriff’s office said.

The three suspects, Joseph Koenig, Nicholas “Mitch” Karol-Chik, and Zachary Kwak – all 18 – face charges of first-degree murder, extreme indifference, the sheriff’s office said in its release. The three were interviewed Tuesday night, according to Kelley.

Alexa Bartell

Any additional charges will be filed in Colorado’s First Judicial District Attorney’s Office, the release said. The three will remain in custody until their first expected court appearance Thursday where they will be “advised of the charges against them,” Kelley said.

CNN has reached out to the public defender’s office to see if the three have attorneys assigned to them.

The arrests came as a result of “cellphone device forensics,” Kelley said Wednesday. Authorities told Bartell’s family about the arrests in the middle of the night, Kelley added.

“They’re just so grateful,” Kelley said while talking about Bartell’s family. “They’re still suffering from the greatest loss possible, but this is the beginning of the journey that they’ll be on next.

“This case touched a lot of people deeply. This was a beautiful young woman with her whole life in front of her who was simply driving home,” Kelley said.

CNN’s Rachel Webb contributed to this report.