A neighbor called 911 to report the blaze March 20 just before 9 p.m. in the 3400 block of Cheek Road.
Investigators called the fire suspicious and said several men with flashlights were seen in the area minutes before the fire started.
Anyone with information about the fire is asked to call Det. Helsius at (919) 560-0880 or Durham CrimeStoppers at (919) 683-1200. CrimeStoppers pays cash for information leading to the arrest of individuals for felony crimes and callers never have to identify themselves.