JEFFERSON COUNTY, Colo. (KDVR) — Three 18-year-olds have been arrested in connection with a rock-throwing crime spree in Colorado that killed a 20-year-old woman.

The Jefferson County Sheriff’s Office (JCSO) said it arrested Joseph Koenig, Nicholas “Mitch” Karol-Chik, and Zachary Kwak. The three men, all 18 years old, were taken into custody at their homes in Arvada, Colorado.

According to a Sheriff’s Office spokesperson, all three men were seniors at three different high schools in Jefferson County. Investigators do not believe they had any relation to the victims in the crime spree.

The three suspects were arrested in connection to the spree that killed Alexa Bartell on April 19. Bartell, of Arvada, was driving when she was hit by a large rock.

All three are accused of throwing rocks, and all are facing charges of first-degree murder – extreme indifference. Additional charges are expected to be filed at a later date.

JCSO said it is unclear which suspect was driving during the crime spree.

This was not the first instance of rocks being thrown at cars that night. A total of five incidents were reported.

Another victim, Nathan Tipton, said, “I have a lot of anger that they would do this. I have a lot of anger that they took somebody’s life.”

JCSO worked with Westminster police, Arvada police and the Boulder County Sheriff’s Office to identify the suspects. The Sheriff’s Office said mobile device forensics and support from the public ultimately led them to the suspects.