LINCOLN–(10/11 Now July 5)–The only survivor of a crash that killed four Gretna teenagers has been released from the hospital.

According to a spokesperson for CHI Health, Roan Brandon is no longer a patient there. The 15-year-old was transferred to the burn unit at CHI after the crash on June 17.

Abigail Barth, 16, Alexandria Minardi, 15, Kloe Odermatt, 16, and Addisyn Pfeifer, 16, died at the scene after their vehicle hit a guardrail and caught fire near 180th Street and Platteview Road, authorities said. All of them attended Gretna High School.

The preliminary investigation revealed that the driver, Abigail, lost control and crashed into a guardrail. The car then caught fire.

Authorities are still investigating but believe that speed was a factor in the crash, he said, but they’re still trying to determine where the teens were coming from and where they were headed.