The bodies 37-year-old Tina Marie Lester and her husband 34-year-old Jonathan Brian Lester were found by their 11-year-old son at their home at 72 Emerald Lane in Broadway, near Old US Highway 421 between Lillington and Sanford on May 14.
The boy said his parents were fine that morning when he left to go shopping with a friend, but when he returned home that afternoon he found his father dead in the kitchen and his mother's body between the kitchen and the bathroom.
Authorities said there was no sign of foul play.
On Friday, an autopsy report revealed several drugs were present in Tina's system, but it was an overdose of morphine that killed her.
An autopsy report for her husband has not been released.
Family members have said the couple was in bad health, both dealing with high blood pressure. They also say Jonathan had suffered two brain tumors and had a bad heart, while his wife Tina had problems getting around.