(NewsNation) — The son and daughter-in-law of an 81-year-old Mississippi woman have been charged after human remains were pulled from a backyard in Jackson.

Police on Monday had issued a missing persons alert for Carol Ryan after a family member said the elderly woman had not been heard from in several months. Around the same time, authorities say they obtained a search warrant for Ryan’s home, where a cadaver dog reportedly prompted an excavation in the backyard.

Human remains wrapped in a tarp were found 6 to 8 feet below the surface. The state crime lab was working on identifying the body, which had been in the ground well before Ryan was reported missing.

The woman’s son, 50-year-old John Ryan, and his wife, Samantha Ryan, 48, were arrested and charged with desecration of a human corpse, police said. They were being held on bonds of $100,000 and $75,000, respectively.

Jackson Police Chief Tyree Jones said Carol Ryan was known to live at the Jackson home with her son and daughter-in-law. They were not the ones who reported the woman missing, he said.

More charges were possible, police said.