Sask. First Nation announces hundreds of unmarked graves found at former residential school site A news release from Cowessess and the Federation of Sovereign Indigenous First Nations did not give a specific number, but said it will be the most found to date in Canada. Social Sharing CBC News · Posted: Jun 23, 2021 5:14 PM CT | Last Updated: June 24 The Cowessess First Nation says it has found hundreds of unmarked graves at the former Marieval Indian Residential School gravesite. There are already also some marked graves at the site.(CBC) WARNING: This story contains details some readers may find distressing. The Cowessess First Nation says it has discovered hundreds of unmarked graves at the site of the former Marieval Indian Residential School in Saskatchewan.