"It appears he was trying to climb up the side of the building," says the unidentified caller.
Mehdy Hazheer was hurt in the fall Friday night. He was in WakeMed's neurological intensive care unit for two days before he died.
Hazheer's family told ABC11 Tuesday their son's death was an accident.
The family said the teen loved to climb, but they believe the backpack he was wearing at the time of his accident caused him to fall heavily, making his head strike the wall.
Severe head trauma led to his death.
The family said it doesn't blame the school.
Hazheer's funeral is set for Thursday at 2 p.m. at Raleigh Memorial Park. Arrangements are being made through Mitchell Funeral Home at 7501 Glenwood Avenue.
The family said Hazheer was an organ donor. Hospital officials notified the family Tuesday that their son's organ donation saved five lives.