EDINBURGH University academic Fergus McInnes has not been seen since a CCTV camera captured him buying a train ticket in Switzerland two years ago today.
He was on his way to attend a conference, but he never turned up and no trace of him has ever been found.
His family believe he may have gone walking and had an accident in the Alps, but there is no evidence to support the theory.
Today his sister Lorna McInnes said the family was still struggling to come to terms with the situation.
She said: “It’s hard to live with the uncertainty of what happened to Fergus nearly two years ago and painful to revisit all the possible scenarios.”
Mr McInnes, 51, from St Leonard’s Bank on the Southside, flew to Switzerland on 9 September, 2014 and was caught by CCTV at the airport buying a return train ticket to the Alpine town of Martigny, 50 miles to the west.
He was due to attend a conference at Idiap Research Institute in Martigny starting the next day.
However, he failed to join colleagues for an evening meal or check into his hotel.
He did not turn up at the conference and he did not catch his return flight on 11 September. Concerned colleagues reported him missing the following day.
Police in Switzerland mounted a search but were unable to find any trace of him.
He is a keen hillwalker and his family thought he might have caught the train to Martigny and decided to go hiking ahead of the conference, then met with some sort of accident. But there is no proof.
Mr McInnes is a former Cambridge maths student and a research fellow at Edinburgh University’s Centre for Speech Technology Research.
His past research has included human-computer interfaces and the evaluation of automated telephone services for BT.
He had battled with depression in the past but had not sought treatment since 2010, and his family – Lorna and parents Bennet and Elizabeth – described him as “upbeat” in the days before his disappearance.
Lorna said: “He remains very much in our thoughts, although as more time passes it gets harder to believe we’ll ever find out what became of him in September 2014. I think we’ll always be hoping that one day we might get some answers, but in the meantime we try to be patient as we continue to look after his affairs to the best of our ability.”
Constable Yocksan Bell, Police Scotland’s Edinburgh division co-ordinator for missing people, said: “We continue to maintain links with police officers in Switzerland, who have led the search to find Fergus. We are also continuing to support Fergus’s family through a family liaison officer.
“We would encourage anyone with information about Fergus’s whereabouts to come forward. They can report this to Police Scotland or to Swiss police.”