Three Denver-area teens cheered each other during a night of throwing rocks at cars — until one of the stones crashed through a windshield and killed a woman, leading to a murder conviction Friday after the trio turned on one another.

A teen was convicted of murder Friday, after he was found guilty of throwing a rock at a car windshield which killed the woman driving. According to the Associated Press, the teen was part of a trio from Denver that reportedly cheered each other on while they threw rocks.

The jury found Joseph Koenig, 20, guilty of first-degree murder for the death of 20-year-old Alexa Bartell, who was killed when a rock was thrown into her windshield and hit her in the head. FOX31's Vicente Arenas has the story.