“It was a very, very difficult day,” says Dallaire, who is now a senator in the Canadian Parliament. “[There were] so many, but it stood out because we lost one of those shining lights, one of those beacon-type guys who influences others.”

Mbaye was part of a small group who had been willing to risk their lives to save others, says Dallaire.

“He had a sense of humanity that went well beyond orders, well beyond any mandate.

 He moved at least half a pace faster than everybody else.”

And he had been about to go home.

“There are only 12 days left before my part in this mission ends,” he had told his wife, Yacine, on the phone three days before he was killed. “Then I will be back in Senegal. So you must pray for us.”

In that last call home to Dakar, he talked a lot about death. “That really upset me,” says Yacine. “He never used to talk like that before. I think the things he saw over there deeply affected him.”

Their two children, a boy, Cheikh and girl, Coumba, were just two and four years old when their father died. It would be two years before Yacine could bring herself to tell them the truth. “Daddy will be home when his mission ends,” she would tell them.

I asked Yacine how she had held the tragedy inside her and not shared it with her children.

“Yes, it was hard, but they would not have understood,” she says. "It was the right thing to do – to protect them from it until they could understand.”

The daughter of the assassinated prime minister, Marie-Christine Umuhoza, is now married with two children of her own.

She and her brothers were flown to France, but the country which had provided a home for the wife and family of the murdered president rejected the children of the murdered prime minister. Instead they ended up as refugees in Switzerland.

Marie-Christine lives in Lausanne, where she works as a psychiatric nurse. She had never spoken publicly about the events of 1994 before, but she told me her chilling tale with great poise and dignity.

She seems to have been able to put a tragic part of her life to one side and move on.

“When I agreed to speak to you, I did it in part so I could pay tribute to the memory of Captain Mbaye,” she says.

 He is – he was – a good person. I owe him my life. If he hadn’t been there, I wouldn’t be here now.”

I heard about Mbaye’s death after noticing an unusual amount of chatter on the UN walkie-talkie network. I heard soldiers talking about a serious incident at a government roadblock in which a UN military observer may have been killed.

“Oh God, I hope it’s not Mbaye,” said a UN aid worker. But he was in denial – he knew it was Mbaye.

I rushed to the roadblock with a Canadian UN officer who also knew but couldn’t bring himself to say it.

When I found the car the body had been taken out. There was blood on the seat and in the footwell.

The next day, when his body was being taken to a plane at Kigali airport for repatriation to Senegal there was no coffin available – the UN mission was operating on such a shoestring, and had been so abandoned by the rest of the world, that Mbaye was wrapped in a large piece of the blue plastic sheeting the UN normally uses for sheltering refugees.

A UN flag was placed on top.

Just before the body was loaded, one of the other Senegalese military observers, Capt Samba Tall, approached me.

“I am a soldier,” Capt Tall said, “but you are a journalist. You must tell the story of Capt Mbaye Diagne.”

Then Capt Tall and I both broke down in tears.