Three hitmen have admitted killing Alan Hogg, 64, and his wife Nott, 61, after they were hired by her brother for £1,175 following family feuds over money, police said.
Mr Hogg was blasted with a shotgun near his swimming pool and his wife was beaten to death with a hammer in the garage of their mansion, detectives believe.
The bodies were found by sniffer dogs two metres deep behind a duck pond outside their home in Phrae, northern Thailand.
They were excavated at 12pm local time and have been sent to hospital for post mortem examinations.
Mr Hogg, from Edinburgh, was the director of a laundry company in the UK and had moved to Thailand several years ago.
His daughter Robyn Hogg, a 31-year-old production assistant, flew to Thailand from the UK after being alerted to her parents' disappearance. She is yet to comment on the tragedy.
After the bodies were found, the three hitmen confessed to the murder and burying the bodies, police said.
The assassins told police they were paid by Mr Hogg's brother-in-law, Warut Satchakit, 63.
Warut, who was initially arrested for stealing the couple's brand new white Ford Ranger pick-up truck, has been arrested again after the bodies were found. He denies any involvement in the deaths.