The three were positively identified as Lisa Kregear, 23; Wendy Camp, 23; and Cynthia Britto, 6, the (Oklahoma City) Oklahoman reported Thursday.
They disappeared after leaving on a trip to Shamrock, Okla., to visit Camp's son, who lives with his father, Chad Noe. Their remains were found by the state Bureau of Investigation in Pawnee County in a grave on property that formerly belonged to Noe's grandmother and uncle, authorities said.
The cause and manner of the three deaths are still being determined, medical examiner's office spokeswoman Amy Elliott said.
Investigators say they found the bodies in May on the property of Grover Prewitt, 50, the brother of Beverly Noe, camp's former mother-in-law. Prewitt was arrested and charged at that time with accessory after the fact -- first degree murder, for his role in allegedly concealing the three were killed and buried, KWTV-TV, Oklahoma City, reported.