More than a year after at least 200 unmarked graves were found at a former residential school in Kamloops, B.C., Indigenous leaders seeking justice for the abuses that took place in Canada's residential schools and are pushing for criminal charges against those who were involved.

Rose LeMay, CEO of the Indigenous Reconciliation Group, told CTV's Your Morning she does not see any reason why there wouldn't be a criminal prosecution, given the number and severity of abuses that occurred.

"There were some reasons perhaps why it didn't occur back in 2013/2014 when we were leading up to the Truth and Reconciliation Commission's final report. There seemed to be some reticence at that point. But I'm not entirely sure that there was ever a good reason not to do criminal prosecution," LeMay said on Wednesday.

LeMay said some of the officials who signed off on funding for churches to run residential schools may actually still be alive, and should be charged for their crimes.

However, some Indigenous groups have said the only way to do this would be through the International Criminal Court (ICC), but that body does not investigate any crimes that took place prior to 2002 – less than six years after Canada's last residential school closed.

LeMay said the criminal case could be a federal investigation, but noted that would likely involve the RCMP. She said this would be a concern given that the RCMP was one of the police forces involved in taking Indigenous children away from their families to residential schools.

She says this doesn't leave many options for criminal charges, but advocates still want to see some sort of prosecution.

Beginning in the late 1800s, approximately 150,000 Indigenous children were separated from their families and forced to attend residential schools, facilities that aimed to replace their languages and culture with English and Christian beliefs. The schools were set up by the Canadian government and most were run by the Catholic Church.

Numerous cases of abuse and at least 4,100 deaths have been documented at the former residential schools, where thousands of confirmed and unmarked graves have been found. Canada’s last residential school closed in 1996.

Pope Francis is expected to deliver an apology to Indigenous people for the Roman Catholic Church's role in residential schools during his visit to Canada this July. He made an initial apology after First Nations, Metis and Inuit delegations met with him at the Vatican earlier this year.

A United Nations special rapporteur is also planning a trip to Canada this summer to examine the "overall human-rights situation" of Indigenous people in light of the unmarked grave discoveries. The UN rapporteur will not be investigating crimes related to the graves during the trip, which LeMay says is a setback for those groups that have been calling for an independent, criminal probe.

"I think a lot of the frustration that may be leading to this demand for criminal prosecution is the fact that the Catholic Church refuses to do the right thing," LeMay said. "I wonder if the Catholic church actually did the morally right thing, gave reparations, sold buildings to cover the penalties that they were expected to pay back almost a decade ago, I wonder if that would let off some of the pressure."

LeMay said all Canadians, not just Indigenous people, want to see the federal government and Catholic Church offer tangible support when it comes to reconciliation, rather than just promises and agreements in principle.

"I think the one thing that will shift this country is the voices of Canadians who want to see something different. That has always made a shift in the dialogue," LeMay said. "Canadians wanted to see Indigenous neighbours doing well."