Missing property developer Kevin McGeever, who was found wandering at the side of a rural road, was mutilated and had an insult carved across his forehead.
Mr McGeever, who is currently in hospital, has told gardai he was abducted eight months ago by armed men but he cannot recall what happened to him after that.
He was discovered in a dishevelled state near Ballinamore, Co Leitrim, on Tuesday night and had lost about five stone in weight.
He had been reported missing to the gardai at Gort, Co Galway, on June 22 last.
The 68-year-old man has told gardai that he was abducted by three masked men at gunpoint from the garden of his mansion home at Craughwell, Co Galway, last May.
He said the kidnappers had demanded a ransom for his safe release but he did not know whether a ransom had been paid. Mr McGeever said he could not remember what had happened to him in the meantime but, as he was being released, he was given a mobile phone and warned to keep it with him at all times.
Gardai said he was feeble and thin when he was found and, apart from the weight loss, he had a lengthy beard and very long fingernails.
He was taken to Mullingar hospital where he was treated for malnutrition and dehydration.
The marking on his forehead was thought to have been cut into him with a knife.
Officers are trying to establish whether he had been held across the Border before he was dumped in Co Leitrim.
Mr McGeever told the couple who found him that he had been thrown out of a van and did not know where he was.
During the boom, he ran a successful property business selling luxury homes in Dubai to wealthy Irish and British clients.
He is currently listed in legal proceedings before the High Court in a case being taken against KMM Properties, which began in 2009.
Catherine Vallely discovered the missing man on the Leitrim-Cavan border on Tuesday night.
She was on her way home to Ballinamore with her partner Peter Rehill when they spotted him in the middle of the road.
"He had red trousers that made me think it was a cone in the middle of the road.
"When the man got into our car he told us he had no shoes on. He said three men threw him out of a van," Ms Vallely said.
"The man said his name was Kevin and he didn't realise he was in Leitrim. He didn't even know the month," she said.
They brought him straight to Ballinamore garda station.
"A female garda immediately invited him in for a cup of tea.
"As he was eating tea and biscuits he asked her if she had any more. He said he hadn't eaten for God knows how long.
"He had a pair of enormous eyes in a very thin face and his cheekbones stuck out.
"He was rubbing his beard with fingers that had long nails. He was very well-educated, well-spoken and polite and articulate.
"He was just skin and bones," Ms Vallely said.
A bag of curry chips was brought to him as gardai discovered that he had been reported missing to their colleagues in Gort last May by his partner, Siobhan O'Callaghan.
"We were told he used to be 16 stone. He was just skin and bones," Ms Vallely added.
Mr McGeever's lavish mansion in Craughwell was empty yesterday.