Authorities have arrested the son and daughter-in-law of Carol Ryan, an 81-year-old woman who went missing, after a body was found buried in their backyard in Jackson, Mississippi.

John Ryan, aged 50, and Samantha Ryan, aged 48, were taken into custody by the Hinds County Sheriff’s Office early on Christmas Eve, according to jail records. Both face charges of desecrating a human corpse, as reported by local news outlets WLBT and WJTV.

The pair was initially detained by the Jackson Police Department for questioning on December 22 regarding Carol Ryan’s disappearance. This was confirmed by Jackson’s Interim Chief of Police and Hinds County Sheriff Tyree D. Jones during a press conference held the next day.

That same evening, authorities secured a search warrant for the home in Jackson where the couple had previously lived with Carol, suspecting it might hold clues to her mysterious disappearance.

Investigators employed the assistance of a specialized scent-detecting dog, which guided them to a “specific location in the backyard” that the sheriff described as being identified as a potential grave.

Excavators were brought in to conduct a dig in the backyard, which uncovered “unidentified human remains” wrapped in “some type of tarp,” he said, adding that the grave was “six to eight feet deep” and contained concrete within it.

Authorities confirmed that a formal death investigation is underway, noting that the identity of the deceased has yet to be determined by the coroner and medical examiner.

“At this time, Carol Ryan will continue to be classified as a missing person,” the Jackson Police Department shared in a statement, “until the remains are conclusively identified through forensic analysis.”

“We’re still not exactly sure if this is the missing person,” the sheriff said in his press conference, “although there’s a strong indication that it is, but of course, we can’t confirm.”

The Jackson Police Department announced on Dec. 22 that a family member had reported Carol missing, saying she had not been heard from in “several months.” The relative who made the report was not John or Samantha, the sheriff later told reporters.

John and Samantha remain in police custody as of Dec. 29, and it’s unclear if they’ve retained an attorney. The husband and wife appeared before a judge on Dec. 24 and received $100,000 and $75,000 bonds, respectively, per WLBT and WJTV.