On the night of March 7, Naazir and Qaadir Lewis pulled into a Shell station near their home in suburban Atlanta, gassed up their black Nissan Altima and bought some water and beef jerky.

As they tossed out trash from the back seat, a basketball bounced out of the car, a fleeting moment of teen normalcy captured on the gas station’s security cameras. The twin brothers drove off into the night, leaving it behind.

About 12 hours later, a hiker discovered their bodies at the top of remote Bell Mountain, nearly 90 miles north near Georgia’s border with North Carolina. The 19-year-olds lay side by side on their backs, with their legs straight and their arms outstretched. Each was found with a colorful, anime-style sword.

A 1911-style .45 caliber Garrison handgun lay on the ground between Naazir’s legs.

The twins' bodies were found on top of Bell Mountain near Hiawassee, Georgia. Eifel Kreutz/iStockphoto/Getty Images

In the weeks and months that followed, their relatives disputed the Georgia Bureau of Investigation’s conclusion that the teens died by double suicide. In a brief statement in May, GBI investigators said forensic evidence from the scene showed that both twins had fired the gun.

This week, CNN obtained the GBI’s exhaustive file on the now-closed case — including documents that reveal new details about the twins’ final days. Autopsy reports show the brothers were each found with a “contact-range” gunshot wound to the right side of their head.

In their final days, one brother FaceTimed a girlfriend to show her a handgun he had obtained. He also ordered ammunition online.