Arson investigators are trying to figure out what sparked a massive house fire in northeast Houston.

According to the Houston Fire Department, the home on Priest Drive and E. Hardy Road caught fire early Thursday morning. Flames engulfed the house, but firefighters managed to get it quickly under control.

Firefighters say nobody was home at the time.

According to the homeowners' grandson, the couple was out for the night. The grandson and mother saw the smoke and called firefighters.

Firefighters say nobody was injured.