Main story: Police mix-up led to family's 6-year agony over lost son »

At the age of 27, the graduate already had spells of working in Hong Kong and France under his belt when he secured a secondment to the Big Apple.

It seemed like another positive stage in a career which his family had seen grow from an eight-year-old boy with a fascination for computers to an undergraduate with knowledge beyond that of his tutors at Marseilles University, where he spent some time.

But barely three months into the trip he disappeared in circumstances which left his family uncertain of whether he was even dead. But even though they have finally been able to identify his body and bring it home to Doncaster, they know they are likely to never establish the true circumstances surrounding his death.

Their plight has been worsened by an apparent mix-up by the US authorities, which failed to cross-reference Mr Massey's details with unidentified bodies recovered in the city.

That meant a relatively simple process was delayed for years and left the family in limbo, unable even to cancel a direct debit for his monthly contact lens prescription.

Yesterday, the Massey family, and friends, attended his funeral in Doncaster but that is unlikely to offer complete closure because his death has never been fully investigated.

With an autopsy conducted at the time providing no cause of death, relatives can only speculate about how the man who was looking forward to returning home for Christmas should end up dead and in the Hudson river.

Following the funeral, his sister Katie spoke of their ordeal: "The first we knew was when his company rang to ask if he'd come home early, because he wasn't at work.

"That was a Thursday and he wasn't due home until the following Monday, he'd just vanished.

"We had been in touch with the police and on January 2 we went out to New York."

That was the start of a long battle for information which, until several months ago, was totally fruitless.

"I wrote to the President of the USA, the mayor of New York, the FBI, the Consul Office and everyone else I could think of. We have a really thick file.

"We nagged and nagged but were all told the same thing, that they were investigating.

"We were worried that he could have died and remained unidentified but were told not to worry because they always check such things."

Those reassurances mean the family continued to cling to the hope that for some reason he was still alive but reluctant to make contact with his parents in Edenthorpe, Doncaster, where he grew up.

It meant they organised a well-attended press conference in New York and Mrs Massey spent time pounding the streets of neighbourhoods frequented by down and outs in the hope of finding her son, when he was already buried in the New York City Cemetery.

As the years passed the hope of good news inevitably faded and as the family wrangled with the complexities of dealing with the estate of a missing man, they decided to apply for a death certificate last summer.

The legal process involved satisfying the court that everything possible had been done to trace him and the circumstances of the case were so touching that the female judge who heard evidence of the family's endeavours had to adjourn the hearing to compose herself.

It was during that hearing that the failings of the New York Police Department, and the glimmer of hope that Richard Massey might finally be identified, emerged.

"We have had six years where we thought we would never know. We might never know how he died but for six years we have wondered where he might be.

"Now we know he is not alive, at least we might start to come to terms with it," his sister said.