MONTREAL - They will walk in silence, light candles and raise money for the many orphans left behind. They will mourn and they will remember.

Rwandans around the world are marking the sombre anniversary beginning this week of the 100-day genocide that left at least half a million of their compatriots dead.

In Montreal, the memorials marking the genocide's 13th anniversary will take place amidst a landmark trial for a man accused of crimes against humanity for his alleged role in the slaughter.

Desire Munyaneza faces seven charges under Canada's new war crimes act, including genocide, crimes against humanity and war crimes. If convicted, Munyaneza, 40, faces a maximum sentence of life in prison to be served in Canada. He has pleaded not guilty at his trial which began several weeks ago.

It's difficult to relive but it's important the trial take place, said Callixte Kabayiza, who fled the African nation as the killing took place.

"If we want to know peace, if we want to at least heal the wounds, the truth must be known," Kabayiza said. "Justice is important."

The killing began on April 7, 1994, the night after Rwandan President Juvenal Habyarimana's plane was shot down near Kigali.

Over the next 100 days between 500,000 and 800,000 members of the Tutsi minority and moderate members of the Hutu majority were slaughtered, most hacked to death with machetes. Hundreds of thousands of others fled the country for refugee camps in neighbouring nations.

"I lost my father that day," said Jean-Paul Nyilinkwaya, who was studying in the United States when the killing began and came to Canada in the midst of it.

"I thought I had also lost my mother and my two sisters but I found out later that they had been hiding with a neighbour."

Nyilinkwaya said the trial and the anniversary bring back terrible memories but "their story is being heard."

Munyaneza arrived in Canada in 1997 as a refugee and was arrested at home in Toronto in 2005.

Jurors at his trial have heard from survivors who have accused Munyaneza of rape and murder.

"He told people to kill us and was standing there, making sure no one would escape," one woman, known in court as C16 in order to protect her identity, told jurors.

"When they slashed the woman next to me, I fell down so they would think I was dead, and I stayed there until they were gone."

The Crimes Against Humanity and War Crimes Act, enacted in 2000, and the trial show that Canada condemns genocide, said Frank Chalk, co-director of the Montreal Institute for Genocide and Human Rights Studies at Concordia University and an expert in the Rwandan genocide.

A Rwandan theatre troupe will perform an award-winning play about the genocide in Montreal on Tuesday.

A conference is scheduled for Friday at the University of Quebec in Montreal and on Saturday a march and vigil are also planned in Montreal. Similar events are to take place in Toronto, Ottawa and around the world.

"It's a way of paying homage to those were killed, those who were executed," Kabayiza said. "It's a way of remembering them. We can't forget."

A lot of victims did not get a proper burial, Nyilinkwaya said. Their bodies still lay undiscovered.

"They were real human beings," he said. "So, when we remember them, instead of saying 'There's one million dead,' you go and say 'This is so-and-so, he had a name, he had a family and this is what he stood for."'

Munyaneza may be the first to go to trial under Canada's new war crimes act but some survivors believe others should also face trial.

"We have other files that we've brought to the RCMP," Nyilinkwaya said.

Another Rwandan man has faced the Quebec courts over the killings in Rwanda. The Supreme Court of Canada says there's well-founded evidence that Leon Mugesera helped to incite the massacre of ethnic rivals in his native country.

Mugesera was ordered deported in a decision upheld by the Supreme Court of Canada, but he reportedly continues to live in Quebec City while he fights a decade-long legal battle to remain in Canada.