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       Flags mark where ground-penetrating radar recorded hits of what are believed to be 751 unmarked graves near the grounds of the former Marieval Indian Residential School on the Cowessess First Nation, Sask.

       HO/The Canadian Press

       The Catholic religious order that operated residential schools in Saskatchewan and British Columbia where hundreds of unmarked graves have been found says it will disclose all historical documents in its possession.

       The Missionary of Oblates of Mary Immaculate operated 48 schools, including the Marieval Indian Residential School at Cowessess First Nation in Saskatchewan and the Kamloops Indian Residential School in B.C.

       “We remain deeply sorry for our involvement in residential schools and the harms they brought to Indigenous peoples and communities,” said a statement.

       Indigenous leaders and others have been calling for the release of all documents related to residential schools.

       Marieval, Kamloops residential schools: What we know about the unmarked graves, and Canada’s reaction so far

       Cowessess First Nation announced Thursday that ground-penetrating radar indicated 751 unmarked graves at its school site. Last month, the Tk’emlups te Secwepemc First Nation said the same technology had detected what are believed to be the remains of 215 children at the Kamloops school.

       In the statement, the Oblates said they have worked to make historical documents available through universities, archives and the Truth and Reconciliation Commission.

       They said the work is not complete because of complications with provincial and national privacy laws. They asked for guidance from organizations familiar with those laws.

       “We further acknowledge that delays can cause ongoing distrust, distress, and trauma to Indigenous peoples across British Columbia, Saskatchewan, and the rest of the country,” the statement said.

       The Oblates said they won’t block access to historical documents they have. They also committed to seeking guidance from First Nations and governments.

       “We will work with bishops and other leaders in the Catholic Church to support full truth in these matters.”

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