LAWRENCEVILLE -- A decisive jury required less than 30 minutes this week to find Malcolm "Low" Johnson guilty of murder, prosecutors said Friday.
Deliberations in the three-day trial began about 3 p.m. Thursday, said Assistant District Attorney Chuck Ross, who prosecuted.
By 3:30 p.m., the jury had returned a guilty verdict on all counts.
In addition to murder, jurors found Johnson, 21, guilty of aggravated assault and weapons possession. Gwinnett Superior Court Judge Karen Beyers sentenced him to life plus 25 years.
According to testimony, Johnson set up a marijuana deal at a Stone Mountain apartment complex on Jan. 30, 2008, with a South Carolina dealer known to distribute high-grade product.
When the dealer, Roscoe Gordon, 31, traveled from his home near Greenville with childhood friend Dedric Thompson, 28, that afternoon, Johnson and another man ambushed them, Gordon testified.
Johnson shot Thompson in the head, killing him in the passenger seat of Gordon's Acura. Gordon was shot in the wrist, head and face but survived.
Thompson and his cohort made off with most of the marijuana stash, worth about $3,500, leaving the victims for dead, Gordon testified.
Two co-defendants are charged in the case.
Johnson's alleged accomplices -- Rosby E. Cobb, of Decatur, and Dalva Ray Wilson, of Stone Mountain -- await their respective trials at the Gwinnett County Jail. Both are charged with murder and aggravated assault. Wilson also faces weapons possession charges.