Tonight we're Tonight we're learning more about how detectives tracked down the two teenagers charged with killing 13-month-old Antonio Santiago. One of the final pre-trial hearings was held today. Detectives have charged 17-year-old De'Marquise Elkins and 15- year-old Dominique Lang in the murder case. Channel 4's Vic Micolucci was inside the courtroom today...with more on WHO led investigators to the two teens... Vic? 3 3 3 VIC LIVE INTRO: We learned a lot. For the first time, on the record, we heard police say that it was Dominique Lang, the 15-year-old suspect, who confessed and helped lead them to De'Marquise Elkins, the teen they say pulled the trigger. 3 PKG:00:36 CLIP 125 "Whoever killed this child, and I was like 'wow, somebody actually had the nerve to shoot a baby in the face? Just to kill a baby, it's not human.'" Detectives say this man, who's now in jail on unrelated charges, played a big part in the arrests of the two teens charged with murder. He says he was living with Dominique Lang's aunt at the time...and after the shooting took place that Thursday morning, she made a revelation.01:50 CLIP 3125 "She said I beleive I know who did this." Algrey Brooks says he took that information to police, after hearing a reward was being offered.Detectives say Lang's aunt, Deborah Obley, is the one who led them to the 15-year-old suspect, and told them she gave him and another teen a ride after the shooting. Prosecutors say that other teen was De'Marquise Elkins. They say after hours of questioning, Lang confessed. CLIP 095 00:11 "He actually did a reenactment basically.He walked investigators through the shooting incident which cooberated the same reenactment provided by Sherry West the day before." With the description from the aunt and Dominique Lang, police say they were able to track down and arrest De'Marquise Elkins...who at the time had... :09 ".22 caliber bullets." ...in his pocket.He denied the allegations. Elkins's defesne attorneys have raised questions about the toddler's parents, Sherry West, and Louis Santiago, pointing out both of them tested positive for gunshot residue, while Elkins did not. The baby's father gave an explanation, saying it must have rubbed off from Sherry West's wound.30:06 "I just saw the bullet hole. I saw the bullet hole for the first time. I touched it like a little kid.I've never had a gun in my life." 3 VIC LIVE TAG: The trial for De'Marquise Elkins is still set for August 19th in Cobb County Georgia.Elkins's sister and mother, who are accused of lying to police about the case and helping dump the gun, are also set to be tried at the same time. There's no word on when Dominique Lang will go to trial. Live in Brunswick, Vic Micolucci, CH4, TLS. QUESTION: In the past, defense attorneys have tried to push back the trial date. Is there any reason to believe that this trial may not start on time?ANSWER: It seems like the judge, the defense and prosecution are in agreement that this thing is going to start August 19th whether they like it or not. So everyone is making final preparations before the case goes to a jury.