The defendants - 24-year-old Anthony Trim, 20-year-old Cortez McClain, both of Lawrenceville, and 36-year-old Walter Simon of California - were found not guilty Thursday of killing 17-year-old Devonte Bowles, who was visiting his cousin in Atlanta before starting college.
They were convicted on other charges that led to sentences of 20 years in prison for Simon and McClain and 50 years for Trim.
Prosecutors said the three were part of a five-person crew that planned to rob a drug house in Lawrenceville. The teen who died also was part of that crew. Prosecutors said the group wanted to steal marijuana.
Someone in the house called 911, and the would-be robbers fled when they heard police sirens. Prosecutors said one of the robbery victims fired at the getaway car, shooting Bowles in the head twice.
He died a week later at a hospital.
Murder and other charges against the suspected shooter, 21-year-old Erick Mocrieffe of Snellville, were dropped in September after a grand jury chose not to indict him.
The lone female suspect, 35-year-old Kara Casey, awaits trial on armed robbery and false imprisonment charges.
Police say Bowles was Casey's cousin.