Authorities say around 4 a.m. Monday, they received a call about two houses on fire on Carnation Lane.
Relatives said they think an electric space heater may have started the deadly blaze.
"My Uncle woke up. He said, I guess he smelled smoke and heard some popping. He got up and the house was engulfed and they all got up and got out," explained family friend Patricia Davis.
Four people were inside one of the homes. Three were able to escape uninjured, but the body of the fourth person was found inside a bedroom of the mobile home by fire officials.
"And they started screaming for the other guy but they never heard. They didn't know if he heard them or not," said Davis.
The victim has not been identified.
The cause and origin of the blaze is currently under investigation by Harnett County Fire Marshal's Office and the Harnett County Sheriff's Office.