Jurors deliberated about two hours before finding De'Marquise Elkins guilty in the March 21 killing of 13-month-old Antonio Santiago in Brunswick. The man's mother, Karimah Elkins, was on trial alongside him and was found guilty of tampering with evidence but acquitted of lying to police.
De'Marquise Elkins' attorney asked for bond for his client while they appealed, which a judge denied.
Prosecutors said Elkins killed Antonio in an attempted robbery. The baby's mother, Sherry West, also was shot.
Another teen, 15-year-old Dominique Lang, is also charged with murder in the case and is set to be tried later.
Sherry West testified during the two-week trial that she was walking home from the post office with 13-month-old Antonio Santiago in a stroller on the morning of March 21. She said a gunman demanding her purse shot her baby in the face after she told him she had no money.
Prosecutors said 18-year-old De'Marquise Elkins and an accomplice, 15-year-old Dominique Lang, are the ones who stopped West. Prosecutors say the older teen pointed a small .22-caliber revolver at West and demanded money. When West refused several times to turn over the money, Elkins fired a warning shot and then shot West in the leg and shot the baby between the eyes, prosecutors said.
The killing in the port city of Brunswick drew national attention, and the trial was moved to the Atlanta suburb of Marietta because of the extensive publicity locally.
Prosecutors have said information from Elkins' mother and sister led investigators to a pond where they found the revolver. Karimah Elkins was standing trial alongside her son on charges of evidence tampering and lying to police. Elkins' sister also was charged with evidence tampering.