Richmond County sheriff's personnel arrested Broderick Tavares Williams, 16, on Friday on murder, armed robbery and firearm charges.
Earlier Friday, police charged Tavaris Lanard Samuels, 18, with murder and possession of a firearm, armed robbery and other charges. He was taken into custody Monday after a holdup at the Augusta Lodge on Gordon Highway, police said.
The motive in the December shooting was robbery, as the suspects had seen Mr. McGee leave a grocery store and tried to steal his gold necklace, police said.
The suspects had gone to school with the victim, according to Richmond County Sheriff's Lt. Scott Peebles.
"We think he (Mr. McGee) was legitimately minding his own business, and we think the evidence we gathered supports that," Lt. Peebles said.
Mr. McGee, described by his mother as a hardworking but quiet bricklayer, was shot in the head while making an early morning trip to the store to pick up two bottles of soda for his disabled uncle.
He was returning by bicycle to his uncle's Bon Air apartment when he was fatally wounded.
Sheriff's Investigator Paul Godden, the lead investigator in the case, said he spoke with the victim's family Friday.
"I think they're still in shock but after a while it will sink in," he said. "They are very pleased."
There remains one open homicide case from 2008. Authorities are still searching for suspects in the death of Robert Lee Smith, 79, who was found dead in his yard in the 1100 block of Kent Street.
Reach Adam Folk at (706) 823-3339 or firstname.lastname@example.org.