Authorities said human remains found in a shallow grave in rural North Texas are those of a missing U.S. Army soldier, five years after they think he was killed.

According to the criminal complaint, authorities arrested Green's mother, Terri Green; his sister, Brittany Jan Green; and his sister's friend, Stephanie Heaston-Corral. All three are charged with tampering with evidence. Their attorneys did not return phone messages Tuesday afternoon.

Brittany Green allegedly told authorities that her brother said he had shot Ramirez twice because he "did not believe in God and alleged that Ramirez reached for a gun," the complaint said. Terri Green helped her son move Ramirez's body from the home's garage to the shallow grave, the complaint said.

Heaston-Corral later used Ramirez's credit card to buy a pizza...