On Thursday morning, Monique Burston sat in court, bracing herself on the shoulder of a man at her side, and listened to how her daughter died, how a 9mm bullet tore through the 21-year-old’s back in a car on Interstate 20 in DeKalb County, Georgia. Burston thought of her grandson. Demarko Cade Jr., 2, used to go to the window and wait for his mom to get home from work every day, Burston said. The young mom would load him into the car and they’d just drive, to nowhere in particular. 'He's still sitting by the window,” Burston said. >> Read more trending news The child’s mother, Airiyuanna Burston, died Oct. 26. She’d been riding in her boyfriend’s Jeep on the interstate in DeKalb County when a gunshot flashed from the back seat, traveling through her seat into her. When police arrived, they found that the boyfriend’s cousin, Gregory Neal, 22, had been seated behind the victim. The cousins made up a story about another driver firing into the car in a fit of road rage. But Neal admitted he’d done the shooting after Detective Krischan Payton told him cops found a shell casing in the floorboard where he’d been sitting, Payton testified Thursday. After “numerous” interviews, Neal offered to take police back to the scene and show them where he’d hidden the 9mm pistol up an embankment. Payton said Neal told him the pistol had been laying on the back seat under his backpack. Neal said he moved the backpack and somehow accidentally fired the gun, which police believe. “It was not an intentional shooting,” the detective said. Payton said he knew of no animosity between the victim and the shooter. Monique Burston isn’t convinced it was an accident and said she wants police to investigate further and hear out her theories. Neal is already facing a felony murder charge. Under Georgia law, the crime doesn’t require intent to kill; it only requires that a death occurred while someone committed a felony. In Neal’s case, it was a felony for him to have the gun at all because he has felony convictions from a burglary case, police said. Before the gun fired, Airiyuanna Burston had been working in a warehouse, was about to start a second job and planned to attend Emory University. She wanted to be a lawyer. Monique Burston hurts for the lost potential and the loss. She worries about her grandson as he waits by the window in the dark. “You can see he's empty,” she said.