Raymond Griffiths, from Hebburn, was last seen on Monday, May 16, and was reported missing on Friday.
Following a search, a body was found yesterday, Sunday, May 22, by the Northumberland National Park Mountain Rescue team.
Formal identification has yet to take place, but officers believe it to be the 63-year-old.
Police do not currently suspect any third party involvement.
A report will be prepared for the coroner.
Detective Inspector Christopher Raper-Smith, of Northumbria Police, said: “This is an incredibly sad update and one we certainly did not hope to deliver.
“Our thoughts remain with his family and loved ones. We will continue to offer them support during this extremely difficult time and would ask that their privacy is respected.
“We want to thank everyone who shared our appeal to help find Raymond, as well as all our officers, partners and volunteers who assisted with our search.”