Jason Smalley of Athens, Texas accidentally shot and killed his friend Stoney Conley in the mistaken belief that he was acting in self-defense.  The two men were smoking meth together when they heard a suspicious noise.  Smalley went to fetch his .22 caliber rifle and aimed at a person he could only see from the waist down.  When Smalley discovered he had shot his friend, he put his gun down and went to tell deputies.

Smalley was arrested and charged with murder.

Source:

Patrick Cunningham, “Sheriff: East Texas Man Sharged with Murder After Shooting Person He Was Smoking Meth With,” ketk.com (July 16, 2021).