Updated

Authorities say relatives of a 9-year-old Oklahoma boy who went missing in 2006 have been arrested and their property is being searched for his remains.

Assistant District Attorney Paul Smith says Rex and Rebecca Clark were arrested Friday in the disappearance of their nephew and foster son, Colton Levi Clark. Smith says the arrest warrants allege first-degree murder and child abuse, but formal charges are pending.

Smith says Colton is presumed dead and investigators are searching the couple's rural Seminole County property for his remains. Smith says it's unclear if the Rexes have attorneys.

Colton was reported missing on April 20, 2006, prompting investigators to search 2,500 acres. At the time, his aunt said Colton didn't want to attend a counseling session and investigators thought he may have run away.