On December 9, 1994, a meeting took place on the Karabakh ceasefire line and an unusual transaction was made.
Two young captive soldiers - Azerbaijani Rauf Budagov and Karabakh Armenian Levon Babayan, both aged 23 - were exchanged for one another and allowed to go home.
The two men shook hands, each finding the other's - like his own - chafed rough by the cold and coated in dirt. Both trembled with emotion.
"I've become a different person, quite different," said Levon. "I don't sleep a wink all night," said Rauf. "And even now I don't believe I'm going home. It's like being born a second time, like coming back to life from my coffin. Basically, you've given me back your life and I've given you yours."
Levon replied, "And what a life, 100 years long.... I wouldn't wish what I've been through on my enemies." Then each man moved on and returned home.
Sadly, the return from the dead of these two men, seven months after the Nagorno Karabakh ceasefire agreement of May 12 1994, was a rare happy ending in what is one of the most ignored and tragic aspects of the unresolved conflict.
As the tenth anniversary of the truce is observed, thousands of people are still reported missing and their fate remains a mystery.
Most independent observers believe that all those still missing are in fact dead. But many relatives refuse to give up hope - and they will be encouraged by occasional cases where captives are traded for money through Georgia.
From the very beginning of the Karabakh dispute in 1988, both sides took hostages.
At the beginning of 1993, a year into the full-blown war, Azerbaijan and Nagorno Karabakh - the latter still unrecognised as a state - formed government commissions to deal with prisoners of war and hostages. Armenia later set up its own commission.
As the fighting raged, the Azerbaijan and Karabakh Armenian sides kept up a constant dialogue and continued to exchange prisoners.
"There were several corridors along the front-line, where meetings, negotiations and exchanges took place," said Albert Voskanian, deputy head of the Karabakh commission from 1993 to 1997. "It all helped us to work realistically and fruitfully. Several hundred people from both sides were sought out and exchanged."
The formal end of hostilities with the 1994 ceasefire, which sealed a de facto victory for the Armenians, resulted in a sharp decrease in captive numbers, but the fate of thousands remained uncertain.
In 1997, the Azerbaijanis stopped working directly with the Karabakh commission. After that, the Karabakh Armenians engaged with Baku mainly through the Red Cross.
Since 1995, an International Working Group - led by Bernhard Clasen of Germany, Russia's Svetlana Gannushkina and Paata Zakareishvili of Georgia - has worked with all sides, going back and forth to visit sites where prisoners might be detained.
The Azerbaijani State Commission says 4,959 Azerbaijanis are still missing in action from the Karabakh conflict, a figure that includes 71 children, 320 women and 358 elderly people. Furthermore, the Azerbaijanis say they have information that 783 people, again including civilians as well as combatants, were taken captive by the Armenians and have not been released.
On the Armenian side, the Karabakh State Commission lists around 600 people as missing, 400 of them civilians.
The vast majority of these missing people have not been heard of for more than a decade, and it is presumed they are dead, buried in graves whose location is known only to a few people or to no one at all.
But every year, a few soldiers still go missing across the front line, generally in places where the trenches of the two opposing militaries run closest to one another. Some of the men may simply have got lost and blundered into enemy lines, others may have got caught on reconnaissance missions, and others still may have been trying to desert.
Each side alleges that the other is hiding captives - and each strongly denies this charge.
The Azerbaijani commission says it does not trust the Armenians. In a statement to IWPR, it said that between 1993 and 1999, the Armenian side consistently said it was holding no more than 50 or 60 captives, yet from 1992 to 2000 the far higher figure of 1,086 Azerbaijanis was freed.
"There is information about a few possible burial sites of Azerbaijani soldiers after certain battles," Viktor Kocharian, head of the Karabakh commission, told IWPR. "From time to time we hand over remains which are discovered in the searches we carry out. But the figure of 5,000 is ridiculous! It should be obvious that it's simply impossible to secretly hold this number of prisoners of war or even human remains within Karabakh."
It has mainly fallen to a partnership of non-government organisations on either side, together with the International Working Group, to investigate the allegations that captives are still being detained.
"To debunk myths, we've had to climb into quarries in Azerbaijan and check out information we'd received that hundreds of Armenian prisoners were working there," Svetlana Gannushkina told IWPR. "We didn't find a single Armenian." To investigate similar allegations about the other side, the Helsinki Initiative 92 group organised a trip by a group of Azerbaijan women to Karabakh last August. Carrying a list of 50 soldiers missing in action, the women were allowed to visit Karabakh's two prisons, one in Shusha (which the Armenians call Shushi) and one in Stepanakert (which the Azerbaijanis call Khankendi) - and found no one.
The three international investigators point out that for purely practical reasons, it is difficult and expensive to keep prisoners over a long period and hide them from prying eyes.
This is not enough to satisfy all the relatives. After the trip to Karabakh, one Azerbaijani mother, Tamara Eyubova, told IWPR, "We are not entirely certain that there are no Azerbaijani prisoners in Karabakh. We were shown one prison and one detention centre, but where's the guarantee that they are not being held in other prisons?" Vera Grigorian, an Armenian mother whose son is missing in action, told IWPR, "We have definite information that there are Armenian prisoners of war and hostages in Azerbaijan. We receive various kinds of information through different channels about this or that person. Former prisoners come to us and identify one and the same person with whom they shared their captivity."
The most explosive allegation made by both sides is that prisoners are being traded for money via their common neighbour Georgia.
Arzu Abdullayeva, a well-known human rights activist who is head of Azerbaijan's Helsinki Committee, spent a long time in the early Nineties investigating this trade, particularly at the market in Sadakhlo in Georgia. In 1994, Abdullayeva personally paid 1,000 dollars that she had been awarded with the Olof Palme peace prize, allowing Azerbaijani father Fikret Mamedov to buy back his son. She said the decision to pay the ransom was made because it was feared that the criminals said to be holding the boy would kill him before normal channels could be made to work.
"People are bought for cash," said Donara Mnatsakanian, whose son Nelson went missing in 1996, two years after the ceasefire. "Today no one makes a secret of that. But I won't name any names because the problem still exists and unfortunately money is just about the only way of freeing hostages."
Donara said that her son was found through the efforts of relatives in Kiev and acquaintances in Azerbaijan. Nelson had grown so desperate in captivity that he tried to commit suicide by jumping out of a window - but he survived. He was finally freed for a cash payment in Georgia four years after he went missing, and after an initial attempt to free him in Tashkent had failed.
Donara refused to answer IWPR's questions as to who was the intermediary, what sum was paid and how Nelson was finally freed, because she didn't want to wreck the chances of a similar transaction helping someone else.
"It's easier to come out with fine slogans about how people mustn't be bought and sold - until your own son is over there," said another Karabakh mother, Vera Grigorian. "The thing is that money, unfortunately, is the last thread that connects relatives on either side of the border."
One desperate Azerbaijani, Hamlet Badalov, has gone to great lengths to secure the release of his son Vugar, who he is convinced is still alive after vanishing in 1993. Badalov paid over some money in return for some news about his son, and then bought a fax machine and waited all night for the promised information.
But as Russian investigator Gannushkina reports, "Eventually a fax came through with a Moscow address and the surname of a man supposedly holding Vugar. I checked - that address in Moscow is the Stanislavsky Theatre, and no one by that name works there."
The experts believe Badalov is the victim of a cruel hoax.
All the relatives of the missing agree that what they want more than anything else is certainty. Not knowing what happened to their loved ones, they say, is worse than knowing for sure that someone is dead.
"We want real help in the search for our relatives," said mother Svetlana Martirosian. "We want to know for sure whether a person has or hasn't died. We need just one thing - true information."
Sadly, ten years after the Karabakh ceasefire, hundreds of families are still waiting to find out the truth.
Editor's Note: This article is a unique collaboration by two journalists from the opposing sides in the Karabakh conflict. The terminology used to refer to aspects of the conflict was chosen by IWPR in London in an attempt to achieve neutrality. It may not necessarily reflect the original wording.
Karine Ohanian is a freelance journalist based in Stepanakert, Nagorno Karabakh. Zarema Velikhanova is a freelance journalist based in Baku.