Authorities have been searching the rural property of an Oklahoma couple for the body of a boy who disappeared in 2006 when he was 9, but aren't saying what new reason led them back there.

A court hearing is tentatively scheduled Tuesday for Rex and Rebecca Clark, who were arrested Friday after authorities obtained a warrant in connection with the disappearance of Colton Clark, their nephew and foster son.

David Hanson, an investigator with the Seminole County Sheriff's Office, said Monday authorities have medical examiners on hand as they search. He says authorities received new evidence that led them to the Clarks' property, but declined to say what it was or where it came from.

It was unclear if the couple had an attorney who could comment for them.