Investigators say 45-year-old Robert Stewart walked-in, opened fire and killed eight people.
Officer Justin Garner was the only officer on duty at the time when he rushed into the Pinelake Health and Rehabilitation Center without backup.
Garner says searching for the gunman was very scary. He described the experience on The Today Show, Monday morning.
"When I went in, like you said, there were doors, hallways, there were rooms everywhere. I didn't know where he was at," Garner said. "It was very scary --very scary."
Garner says he thought the initial call was a misunderstanding. He says he realized something was wrong after noticing cars in the parking lot riddled with bullets.
Garner shot Stewart in the chest and Stewart shot Garner in the leg. The 25-year-old officer thinks they must've fired at the same time, because he says he never heard the shot.
Police have not commented on a motive for the shooting, but Stewart's estranged wife worked at the nursing home. She says she hid in a bathroom inside a locked Alzheimer's patient unit and was not injured in the attack.
The Moore County prosecutor said the shooting is not considered a random act of violence.
Stewart is charged with eight counts of first-degree murder. He remains in a state prison hospital in Raleigh.