A North Texas couple is behind bars, accused of burying their special needs son in the backyard.

The investigation began Tuesday, Oct. 14, at a home on White Oak Lane in Burleson, south of Fort Worth.

“You might think you know your neighbor, but you don’t,” said Betty Noyola, who lives next door.

Burleson police say they were called to the home for a welfare check on the victim, later identified as 26-year-old Jonathan Kinman. A friend of Kinman’s mother contacted police after she reportedly posted on Facebook that he was deceased.

When officers arrived, police say Kinman’s mother, December Mitchell, gave conflicting information.

“She said he was taken to Huguley Hospital and pronounced there and we followed up with that and that was not correct,” said Burleson Police Deputy Chief Doug Sandifer.

Investigators say they obtained a search warrant and discovered Kinman’s body buried in a shallow grave in the backyard. His body was exhumed and taken to the Tarrant County Medical Examiner’s Office. The cause of death has not yet been determined.

December Mitchell and Kinman’s stepfather, Jonathan Mitchell, were arrested. Both are charged with tampering with physical evidence with intent to impair a human corpse, a second-degree felony. Each is being held on $250,000 bond.

A relative told NBC 5 the family has no comment.

“We want to offer our condolences for the friends and family members who cared for Jonathan and came forward to report this,” said Sandifer. “This was also very heartbreaking to our officers on scene and staff to handle.”

Sandifer said Kinman had Russell Silver Syndrome, a rare genetic disorder that affects growth. Police believe Kinman had been deceased for one to two days before he was found.

Noyola said the couple moved in next door two years ago and she never saw the victim coming or going.

“They knew I have a special needs grandchild and they never one time mentioned they had a special needs child,” she said.