Property developer Kevin McGeever did not leave any forwarding address for gardai when he was discharged from hospital yesterday.
The Mayo-born businessman had been undergoing treatment at the Midlands Regional Hospital in Mullingar since he was found wandering a rural road outside Ballinamore, Co Leitrim, almost a fortnight ago.
He told gardai he had been held captive for the previous months by kidnappers, who demanded a ransom for his release. But since then he has been unable to supply any details about his captivity, why he was abducted or by whom.
One garda officer said last night: "He left the hospital and did not indicate to us where he was going. We will continue with our inquiries but have no idea where he intends to stay in the short term.
"But I am sure we can track him down if we need to talk to him again."
Mr McGeever (68) gave a statement to gardai at Ballinamore after he was taken there by a couple who had found him on the roadside, and also spoke to investigating officers from Gort while in the hospital.
But gardai acknowledge they have made little progress in solving the mystery of his whereabouts since he says he was abducted by three armed men from the garden of his mansion home in Craughwell, Co Galway, last May.
He was reported missing by his partner the following month at Gort station. Gardai say that as far as they are aware no ransom was handed over prior to his release.
Relatives of Mr McGeever last night expressed their surprise that he had been discharged from hospital. His family, who live in Foxford, Co Mayo, said they were unaware he was due to be discharged.
"We have been in the UK for the past five days and had no idea that he was getting out," said one family member.
A former business associate said he believed Mr McGeever would not return to his Galway mansion, which has not been lived in for some time.
"I'd imagine he'll go to Dublin. The house is not even liveable, none of the rooms is finished. But that place will be full of unhappy memories from workers picketing outside demanding they get paid," he said.
There was no sign of life at the multi-million euro mansion in Craughwell. In Dublin, at the apartment he shared with his partner Siobhan O'Callaghan prior to his disappearance, there was no answer at the door.
A neighbour said she had not seen Ms O'Callaghan and did not know her location.
Another neighbour, who had moved into the complex in recent weeks, said he had been completely unaware that Mr McGeever had ever lived in the premises, and it was a "quiet" location.
Meanwhile, gardai in Gort, Co Galway who are dealing with the case are now studying CCTV footage from the area where Mr McGeever was discovered in Co Leitrim.
They are also seeking help in tracing the vehicle that Mr McGeever was travelling in before he was dropped at the roadside.