De’Marquise “Marky” Elkins, 18, was found guilty on Friday of shooting 13-month-old Antonio Santiago in March in Marietta, Georiga, it was reported.
WSB-TV reported that jurors deliberated Friday before handing down a guilty verdict in the March 21 slaying.
His mother, Karimah Elkins, was also found guilty of tampering with evidence in the case, reported The Associated Press
Elkins killed the baby as part of an attempted robbery.
Santiago’s mother, Sherry West, was also shot.
Another teen, 15-year-old Dominique Lang, is also charged with murder in the case and is set to be tried later.
The Associated Press contributed to this report.