Canada's Defence Ministry has confirmed this version of events; the UN military leadership has not, although the two versions do not differ greatly. The only point of contention appears to be whether the Serbs lined the soldiers up against a wall, firing squad-style, before shooting at them.
While Unprofor admits the soldiers were detained and there was 'some shooting near' the Canadians, a UN spokesman, Major Idesbald van Biesebroeck, dismissed the 'mock execution' version of the story as a serious exaggeration. 'It was a serious, but routine incident . . . The lives of Canadian soldiers are regularly in danger,' he said on Wednesday.
Whether up against the wall or not, what is certain is that the UN sought at first to bury and then downplay the incident. The reason for the UN's response may have something to do with Unprofor's increasingly uncertain future.
UN military officials know that such an incident would almost certainly provide grist for the mill of governments calling for Western troops to abandon Bosnia.
In recent months, as Bosnia has entered the brutal endgame of a brutal war, its sufferings have failed to grab the headlines. European officials, most notably the Foreign Secretary, Douglas Hurd, have discouraged media attention on the former Yugoslavia and have taken advantage of this lull in public attention to shift the argument from 'what should we do?' to 'when should we leave?'.
During a radio interview last week, Mr Hurd was so obviously gobsmacked by a BBC reporter's temerity in suggesting that British troops should remain in Bosnia as long as people there were hungry and needed help, that he repeated the question, almost choking on the words as he did so. 'Forever? Forever? . . . Are we willing to . . .' Mr Hurd sputtered incredulously.
'Why not?' insisted the reporter.
'Because if they (the warring sides) believe we are going to do it forever then there is less incentive to reach a peace agreement,' Mr Hurd replied.
Mr Hurd's comments on Monday came less than a week after another Government official, Douglas Hogg, also hinted at a British withdrawal. 'There is a real job to be done here. Therefore, there are many inhibitions about leaving and reasons why we should stay, but clearly one has to consider how much longer we want to play such a prominent role,' Mr Hogg, a Foreign Office minister, said during a visit to British troops in central Bosnia.
Add these remarks to even more forceful statements by both the French and Spanish governments that unless there is a viable peace deal soon they are going to pull their troops out, and it is easy to see why the UN in Bosnia would be anxious over the Canadian mock-execution story.
Although some of this talk is posturing aimed at scaring the Bosnian government into dropping its objections and agreeing to a three-way carve-up of the country, there is serious consideration of a spring pull-out by both Britain and France - the two largest forces operating in Bosnia.
Such a move would be a disaster for millions of Bosnians dependent on the UN for food and medical aid. It would also be a reversal of the only Western 'policy' for the country and the final betrayal of an internationally recognised state.
The British and French governments, for the most part, have treated Bosnia as an intractable problem in which outsiders could do no more than comfort the wounded and feed the starving. From the outset of the fighting almost two years ago, the only military involvement in Bosnia that Britain and France would countenance was the humanitarian role that they began with Spain in the autumn of 1992. Any other option that sought to stop ethnic cleansing, prop up the Bosnian government or roll back Serbian military gains, such as the US- backed lifting of the arms embargo for the mainly Muslim government, was rejected outright by Britain and France as a threat to the 'vital' humanitarian operation.
Withdrawal from Bosnia now would not only represent an admission of Western failure, but would abandon millions to their fate and could lead to a massive influx of asylum-seekers into Europe.
One of the main justifications that Britain and France used for their humanitarian mandate in Bosnia was to contain the conflict within the former Yugoslavia, both in terms of the fighting and refugees. The idea of involving the UN High Commissioner for Refugees in Bosnia with military support was to feed civilians in their own country, so they would not become refugees.
But as one senior UNHCR official said privately last week: 'Our lives are going to be even more impossible than they are now if we don't have military escorts. And if 3 million people are left without food and proper shelter, then they are going to leave and come knocking on Europe's door. Paris and London had better consider that possibility before any pull-out, unless they are prepared to let them die.'
According to Ministry of Defence leaks, contingency planning has already begun for a potentially dangerous British withdrawal from its humanitarian mission some time this spring. Army planners are expecting that once the final decision for withdrawal becomes known in Bosnia, the local population, fearing the worst, will become unco-operative and possibly obstructive. The army is preparing for harassment by a desperate population as well as attempts by various militias to raid the departing troops for weapons.
Why take this risk? Why abandon the only policy this far down the road? The main argument now being put forward by proponents of a UN withdrawal is that the UN operation, which sustains about 3 million people, is prolonging, not easing, the war.
It is true that roads cut out of mountains and improved by British troops to ease access for food and medical convoys have also made it easier for Bosnia's three warring factons to move troops and guns. It is also true that UN provisions bolster the flimsy economies of all three factions. And much of UN food for women and children ends up in the stomachs of soldiers, while fuel for hospitals goes to keep tanks running.
If such supplies did not exist, those supporting a pullout argue, then pressure would mount on Serbs, Muslims and Croats to sue for peace. Without the UN operation, they say, warlords and gangsters controlling roads and the fighting would lose important sources of cash, such as the ability to sell places on lists for UN-sponsored population exchanges.
What the arguments do not take into account, however, is that without the UN there may not be any lifesaving exchanges at all. The war economies, however, would continue. The harsh regime of sanctions against Serbia, according to some American intelligence analysts, is on the point of collapse, as the economies of the surrounding countries, such as Romania and Hungary, even Greece and Albania, can no longer afford to enforce a ban with a traditionally important trade partner.
A UN military withdrawal will, in the end, only affect the victims of the war, the Bosnians themselves.
The irony, according to Balkan experts, is that much of Bosnia's military gains, especially in central Bosnia, are linked to the UN presence, which, despite views to the contrary, does have a restraining effect on Serbs and Croats. 'To pull UN forces out now, when the Bosnian army is doing so well, is to guarantee its defeat,' said one independent analyst.
Proponents of withdrawal cite the difficulties of UN troops in carrying out their tasks as another reason to leave. The UN commander in Bosnia, Lieutenant-General Francis Briquemont, does not agree. On Thursday, he said the UN and the European Union should spend less time passing resolutions on Bosnia and concentrate instead on sending sufficient numbers of troops to do the job. In 1994, Bosnia needs commitment, not abandonment.