Adrian Prout, handcuffed to a police officer, spent about 25 minutes at his Gloucestershire farm, The Guardian reported. Prout and his escort were in a wooded area on the property.
Kate Prout, 55, vanished in November 2007 while she and her husband were in the middle of an acrimonious divorce. Her husband was convicted of the killing and sentenced to life with a minimum of 18 years.
A vocal group of supporters had insisted Prout was wrongly convicted. But he failed a lie detector test arranged four months ago by his fiancee, Debbie Garlick.
Don Cargill, the polygraph expert who administered the test, told The Guardian he convinced Prout to take it because it could prove his innocence. But he said after the test suggested Prout was lying he told him: "I'm looking at a murderer."
The Gloucestershire Constabulary spent hours searching Redhill Farm in Redmarley after Kate Prout disappeared. Detective Superintendent Simon Atkinson warned finding the body could take days, The Daily Telegraph reported.
"Our main priority now is to recover Mrs. Prout's body and enable her family to have some closure after the long ordeal they have been through," Atkinson said.