Twenty-five years ago on this day, Florence Ngirumpatse, head of personnel of the United Nations in Rwanda, was slaughtered alongside her husband, five other adults, and the eleven children in her keeping. The tragedy, which took place five weeks into Rwanda’s 1994 genocide, was compounded by the fact that the group were murdered the night before Florence was to be saved. How was it possible that Florence would be able to hide for more than a month, only to be discovered and killed the night before her rescue?

My best friend, UN humanitarian Gregory ‘Gromo’ Alex, always maintained that something just didn’t add up. Florence had been making desperate telephone calls to the UN for help before finally, in mid-May, Gromo got the go-ahead from the UN to dispatch an armed personnel carrier to evacuate her. The operation was scheduled for the morning of 16 May. But just hours before the rescue team arrived, Florence and those she was protecting were hacked to death.

I don’t know what to make of his claim. Gromo was serious and never prone to exaggerations. Unfortunately, he died a few years ago, in the midst of managing a World Bank operation to encourage fighters of a hardcore militia under the command of former Interahamwe leaders to repatriate from Eastern DRC to Rwanda. Initially we feared he had been poisoned, but it turned out it was cancer that took him from us.

The conclusions of the UN’s internal investigation were damning – in a 2004 story in the New York Times, I accused the UN hierarchy of a ‘don’t tell me, I don’t want to know’ form of bureaucratic inertia. Ultimately I, at that point the secretary general’s representative in Burundi, resigned from the UN, in part as a result of the story.

My resignation however did not mean the end of my pursuit of this case, quite to the contrary. The reasons of my continued commitment to understanding what truly happened to Florence have much to do with trying to get the institution, the guarantor of the integrity of the Genocide Convention that I once so proudly served, to understand the damage to its credibility that having taken no action on this case represented. But more importantly, I have done so to honour the memory of the UN national staff murdered that night.

A little over a month ago, a crowdfunding campaign was launched with publishers Unbound. It is one of two intertwined parts to seek justice. The mixed-medium book wishes to tell this story and honour the memory of colleagues murdered. A significant portion of whatever revenue is generated from the sales of the book once published will go towards covering the costs of the ongoing legal process in France.

A few days ago, I was informed by the head of the UN’s legal office of the organisation’s full commitment to identify and share with the French legal authorities any and all documentation that it has that could be relevant for the case. Twenty-five years on there is the beginning of progress. Hopefully, the organisation will go further and finally do justice to our murdered colleagues.

Charles Petrie is a former UN official and author of The Triumph Of Evil