The Canadian Association Against Impunity, a coalition of human rights groups and non-governmental organizations, filed a last-ditch plea to the Supreme Court of Canada on Monday.
The groups allege that Anvil Mining Limited provided logistical support to the Congolese military who raped and murdered people as it crushed a rebel uprising in 2004, killing as many as 100 people in the port city of Kilwa.
That support allegedly included planes, trucks and drivers instrumental in ending the conflict. The port was key to the operation of a copper mine, the exit point for $500,000 worth of copper and silver every day.
Nearly eight years later, victims' relatives say they have no choice but to turn to Canadian courts.
"We've been fighting for years and what we want is justice," Dickay Kunda said Sunday in a phone interview from Congo. "Our wish is to have Canada help us get justice."
Kunda says his 22-year-old sister, Dorcas, died after being raped by soldiers. His father, a policeman, was badly beaten and tortured while in military custody. He never recovered and died in November 2009.
Anvil Mining, which had offices in Montreal but has since been acquired by another mining company, has denied any culpability in the Kilwa incidents and said logistical support was requested by authorities.
The civil suit has been making its way through the courts for some time.
In January, Quebec's Court of Appeal overturned a 2011 lower-court ruling that had paved the way for it to be heard in Canada.
The appeal court ruled that Anvil's Montreal office was not involved in any of the decision-making that led to a massacre, making it inappropriate to hear the case in Quebec. It also ruled that victims could have sought justice in Congo or Australia, where the company also operated.
Last April, a lower-court judge had rejected the notion that the links between Quebec and Anvil were insufficient.
If the Supreme Court decides to hear the case, advocates say the ruling could have major implications on whether Canadian companies can be held accountable for their involvement in human rights violations committed abroad.
"I think this case is a really important one and the facts that we've alleged are so stark that it really is the kind of case a Canadian court needs to hear," said Matt Eisenbrandt, legal director for the Canadian Centre for International Justice, one of the NGOs involved.
"It can really set the ground rules for whether corporations can be sued when they are involved in human rights violations."
A Chinese company called Minmetals Resources Ltd., with headquarters in Australia, acquired Anvil earlier in March for $1.3 billion.
Sally Cox, a company spokeswoman, denied any wrongdoing on Anvil's behalf.
In an email, Cox said the incident in Kilwa has been subject to numerous investigations and court proceedings, and "no findings adverse to Anvil or any of its employees have arisen."
The attempt at civil action in Canada followed a military trial, held in Congo in 2007, where nine soldiers and three former employees of Anvil were acquitted of charges, leaving no opportunity for civil recourse.
A 2010 United Nations report said the trial had the potential to set "an important precedent in terms of corporate accountability" but "failed to meet international standards of fairness."
"The Kilwa case demonstrated the difficulty in proving the legal responsibility of private companies in the perpetration of human rights abuses and violations of international humanitarian law," the report said.