This case sticks with me. Why did Justin do this? Was there signs of mental instability? Was it drug or alcohol related?

Amber Nicole Carlson was a 19-year-old University of Wyoming nursing student from Denver whose life ended in Laramie in the early hours of July 16, 2006. She had been at an off-campus gathering with friends when neighbors heard cries for help and called police. Officers found Carlson among three young people dead at the house.

On July 19, 2006, police announced the incident as a double homicide-suicide. Authorities said 20-year-old Justin Geiger shot Carlson in the head with a high-powered rifle, then killed 20-year-old Adam Towler with a knife before turning the rifle on himself. A fourth student, 19-year-old Anthony Klochak, survived with knife wounds and injuries sustained while fleeing and cooperated with investigators. No arrest or prosecution followed because the person identified as the attacker was dead at the scene.

Police said they did not know an exact motive, and coverage described the killings as a mystery that remained unresolved in public. If anyone knew Amber or was at that gathering, did she have conflicts or connections that might explain what happened that night?