Elkins faces life in prison if convicted of murder. His youth spared him a possible death sentence. At the time of the shooting he was 17, too young to face capital charges in Georgia.
Police say the motive was as banal as the slaying of a toddler was shocking. Investigators concluded that Antonio was killed during an attempted street robbery as his mother, Sherry West, was strolling home with the child from the post office. West said a gunman demanding cash shot her baby in the face after she told him she had no money.
"He kept asking, and I just said 'I don't have it,'" West told The Associated Press the day after the slaying. "And he said, 'Do you want me to kill your baby?' And I said, 'No, don't kill my baby!'"
West was shot in the leg, and another bullet grazed her ear. Witnesses called 911 and rushed to her aid. None saw the shooting, but they watched as West tried to revive her son using CPR. "No, the baby's not breathing," one caller told a 911 operator.
Police say Elkins had an accomplice, 15-year-old Dominique Lang, who has told investigators Elkins fired the gun. Lang also is charged with murder but will be tried later. He's expected to be a key witness against Elkins.
Both prosecutors and Elkins' defense attorneys declined to comment before the trial, citing a gag order by the judge. The boy's mother also declined to talk.
Kevin Gough, a public defender who is Elkins' lead attorney, has strongly suggested in pretrial motions that the real killers are the child's own parents.
"Other evidence of record suggests Sherry West is mentally unstable, gave several inconsistent accounts of how the crime transpired, and had a financial interest in the death of her son in the form of an insurance policy," Gough said in a court motion filed Aug. 5.
Defense attorneys have said in court filings they have audio recordings and documents showing the child's mother had dealings with Gerber Life Insurance Co. According to its website, Gerber Life sells life insurance policies for children starting as early as infancy. Coverage runs from $5,000 to $50,000.
Ashley Glassey, West's 21-year-old daughter, told television station WTLV of Jacksonville, Fla., soon after the shooting that her mother called her after Antonio was killed and asked, "How soon do you think the life insurance policy will send me a check?"
One of Elkins' lawyers interviewed Glassey on July 30 in Woodstown, N.J., where she was in jail for failing to appear in court in an unrelated case. According to a transcript, Glassey declined to confirm the story. "I don't want to incriminate anyone," she said.
Defense attorneys also point to lab tests by the Georgia Bureau of Investigation that found traces of gunshot residue on swabs taken from the hands of West and the boy's father, Louis Santiago. Reports filed in court say the GBI found a single microscopic particle of gunshot residue swabbed from the father's hands, while more than five particles showed up in swabs from West's hands.
The GBI report cautioned that gunshot victims can end up with residue on them. During a preliminary court hearing, Santiago said he touched the bullet wound on West's leg before his hands were swabbed.
In a court filing Wednesday, District Attorney Jackie Johnson argued that Elkins' defense lawyers have made "false, inflammatory and misleading statements" about the case.
While the toddler's mother identified Elkins as the shooter in a photo lineup, police say much of their evidence against the teenager came from his own family and the younger teen charged as his accomplice.
Investigators have testified that Lang told police he and Elkins were trying to rob a woman pushing a baby in a stroller when Elkins pulled a gun and shot them both.
Lang's aunt, Debra Obey, told police her nephew and Elkins came to her for a ride the day of the slaying. She said Elkins ducked down in the back seat of her car, as if he was hiding.
Four days after the shooting, police said information from Elkins' mother and sister helped lead investigators to a pond where they found a .22-caliber revolver. Both women were charged with evidence tampering. Elkins' mother, Karimah Elkins, also was charged with lying to police. Prosecutors say Elkins' mother and an aunt gave police conflicting alibis for his whereabouts at the time of the shooting. Karimah Elkins is scheduled to stand trial alongside her son.
Meanwhile, prosecutors say Elkins shot somebody else 10 days before the toddler was killed. Wilfredo Calix Flores has identified Elkins as the man who shot him in the arm during an attempted street robbery March 11. Police say Flores was shot with a .22-caliber bullet.
The judge has ruled that jurors can hear about a statement police say Elkins made the day after the killing. Police investigator Roderic Nohilly testified at a pretrial hearing that he and officer Cody Blades were escorting a handcuffed Elkins when the suspect said, "Y'all ain't got no gun. Y'all ain't got no fingerprints." He then referenced an acquittal.
The investigator said Blades just smiled at Elkins, who responded: "Oh, y'all got the gun?"