The RCMP has launched an investigation following news that children's remains may have been discovered near a former residential school in Kamloops, B.C., a move criticized by the former chair of the Truth and Reconciliation Commission.

Retired senator Murray Sinclair told a House of Commons committee Thursday he was advised the RCMP was launching the investigation into "the bodies that have been located in Kamloops.

"And they are now beginning to question those that have made this story available."

The Tk'emlúps te Secwépemc First Nation announced last week that preliminary findings from a survey conducted by a specialist in ground-penetrating radar indicated the remains of around 215 children could be buried on the site.

Sinclair criticized the police involvement, accusing the RCMP of "intimidating" people involved with the search. He said Mounties should "not be pursuing those who are revealing information," such as researchers.

"The young lady who was the one who did the research on the ground-penetrating radar, for example, was quite scared of the ... approach that the RCMP have taken with her," he said.

"And I don't blame her. And my advice to her and others has been to make sure that she has legal counsel available to her so that she is not mistreated going forward."

Sinclair also told the committee he wants an independent investigation to examine all burial sites near former residential schools. He said such a probe should not be run by the federal government, but should be overseen by a parliamentary committee that will ensure that it is done in a proper way.

He said there are too many unanswered questions, such as how many burial sites exist in Canada, where they're located and how many children are buried in them.

A RCMP detachment in B.C. later confirmed that it has opened a police file, but in a statement said the local First Nations band remains the lead on the investigation.

"The Tk'emlúps Rural RCMP has attended the site, participated in meetings, and will continue working closely with the Tk'emlúps te Secwepemc community leaders in determining the next steps and the best way to be involved in any investigative avenues explored going forward, while at the same time being supportive, respectful, and culturally sensitive to the indigenous communities that are impacted," said detachment commander Staff Sgt. Bill Wallace in the statement.

The Truth and Reconciliation Commission's report on Canada's residential school system details the harsh mistreatment of Indigenous children at the government-funded, church-operated institutions, where ongoing research says at least 4,100 children died in a climate of neglect.

Sinclair said he has heard from about 200 residential school survivors over the past week who have shared their grief and frustration over the news from Kamloops. He said uncovering the full truth is important for both the survivors and their families, as well as the families of those who worked there.