A Texas couple faces charges after their adult son with special needs was discovered dead and interred in a shallow grave behind their Burleson home.

December Marie Mitchell and Jonathan James Mitchell have been charged with tampering with evidence and fabricating physical evidence with the intent to impair a human corpse, according to an announcement by the Burleson Police Department on Monday.

The police were called to perform a welfare check on October 14 for 26-year-old Jonathan Kinman.

“During the welfare check, it was indicated that Kinman might be deceased and possibly buried in the backyard of the residence,” authorities reported.

Kinman’s mother, December Mitchell, and his stepfather, Jonathan Mitchell, were taken into custody at the scene. The following morning, officers returned to the property and unearthed Kinman’s body from a shallow grave in the backyard. The remains were sent to the Tarrant County Medical Examiner’s Office for an autopsy.

Investigators are now awaiting the results of the autopsy.

The Mitchells remain in the Johnson County Jail, where they are being held on $250,000 bonds each.

Police declined to provide further information about the case, saying that the city of Burleson had determined that release of any further records “would interfere with the detection, investigation, or prosecution of an open or pending criminal matter,” Law&Crime reported.