ALBANY – For reasons that remain a mystery, David Lang shot his brother once in the head with a .22-caliber rifle in the driveway of their small, struggling farm in Essex County on June 19, 2012.

When David Lang called 911 that day, he freely acknowledged shooting his brother, Russell. When the police dispatcher asked Lang whether he had been drinking, he reported, “Of course I’ve been drinking. … I drink every goddamn day!”