MARIETTA, Ga.  — An 18-year-old man accused of fatally shooting a baby in a stroller during a robbery attempt in coastal Georgia twice counted down from five and threatened the baby before the deadly shot, his teenage co-defendant testified Thursday.

Dominique Lang took the stand at the murder trial of De’Marquise Elkins, who is accused of shooting 13-month-old Antonio Santiago on March 21. Police say the 15-year-old Lang was an accomplice, and he is also charged with murder and will be tried at a later date.

The killing in the port city of Brunswick, not far from Savannah, drew national attention, and the trial was moved to the Atlanta suburb of Marietta owing to extensive publicity.   faces life in prison if convicted of murder. At the time of the shooting he was 17, too young to face the death penalty if convicted under Georgia law.