Her grandfather was so distraught over being forced to attend a Catholic boarding school for Indigenous children that even years later he would not step into a Catholic church.

But Christine Diindiisi McCleave never really learned what happened to him there — a common story among Native Americans trying to understand ancestral histories shadowed by trauma and cultural devastation.

"The U.S. and the churches have never been held accountable for this genocide," she told hundreds of Indigenous people gathered recently in south Minneapolis to honor boarding school survivors.

Recent findings of hundreds of unmarked graves near Canadian boarding schools for Natives, following the work of Canada's Truth and Reconciliation Commission, has spurred hope for Diindiisi McCleave and other advocates that a similar reckoning will come to the United States.

She could play an important role as leader of the National Native American Boarding School Healing Coalition (NABS), a nonprofit in Minneapolis formed a decade ago after a gathering of leaders from both countries discussed the need for a truth and reconciliation process in the U.S.

The coalition was charged with increasing public knowledge and healing regarding the forcible removal of Native children from their homes to attend government and church-run boarding schools so they could "assimilate" into white society, a policy from 1869 until nearly a century later.

Students often encountered abuse. They were forbidden to speak their language and practice their religious and cultural traditions, and some were never brought home.

Diindiisi McCleave was appointed the first CEO of NABS in 2015 and for several years was its sole employee. Investigating decades-old information about 367 American boarding schools proved arduous, and the coalition grew slowly. It filed Freedom of Information Act requests with the Bureau of Indian Affairs for details on the boarding schools, but the agency countered that it didn't do research — so NABS had to compile data of its own.

Several years ago, Diindiisi McCleave and her colleagues traveled to Winnipeg to meet with the National Centre for Truth and Reconciliation (NCTR), which carries out the work of the Truth and Reconciliation Commission and houses the materials collected during that process. The U.S. and Canadian organizations began working out the details of a partnership, kicking off their collaboration with a digital map of Indian boarding schools in both countries that's expected to be completed soon.

NCTR senior archivist Jesse Boiteau said the digital map project brings awareness to the research of both institutions and shows "how the impacts of residential schools were not isolated to only Canada, but it was a North American phenomenon."

Canada's commission was formed in 2008 as a result of the Indian Residential Schools Settlement Agreement, the largest class-action settlement in that country's history, between the government and 86,000 people who attended Native residential schools.

The agreement set aside millions to fund the Truth and Reconciliation Commission, which operated until 2015 and concluded that Canada had pursued a policy of "cultural genocide."

Diindiisi McCleave met in Washington with then-U.S. Rep. Deb Haaland, D-N.M., to talk about legislation establishing a commission like Canada's. The result, which she helped write, was the Truth and Healing Commission on Indian Boarding School Policy in the United States Act.

Haaland introduced the bill last fall with U.S. Sen. Elizabeth Warren, D-Mass., though Congress did not act on it during the presidential election season.

Then in May, unmarked graves and remains of more than 1,000 people, mostly children, were located near a handful of Canadian Indigenous boarding schools stretching from British Columbia to Saskatchewan.

Haaland, who this year became the first Native American Secretary of the Interior, announced in June that her department would launch a massive review of America's Indigenous boarding schools and identify possible student burial sites, with plans to issue a report in April.

Diindiisi McCleave applauded the move, though she said the scope of the issue is so large that she doubts a report will be ready by then.

Meanwhile, the Canadian reports prompted many messages at NABS from not only the media but also tribal citizens.

"When that happened it really not only brought a lot of media attention, because the general public who in this country largely does not know about this history was in shock ... but [for] the Native communities, it brought up all the unresolved grief, all the family history, personal experience and intergenerational trauma that was the result of these schools," Diindiisi McCleave said.

The trauma ran so deep that many seldom spoken of it — which made efforts to record the history all the harder.

Diindiisi McCleave's own family had shown her that. A citizen of the Turtle Mountain Ojibwe Nation, she knew that her late grandfather had attended Indian boarding schools. But even years later, he'd say, "I don't want to talk about it." He nearly missed her uncle's wedding on the Turtle Mountain Indian Reservation in North Dakota because he wanted nothing to do with church. Haunted by his tribulations, she wrote a master's thesis on Native American spirituality and Christianity.

Though boarding school history and healing have been her longtime passion, Diindiisi McCleave is not sure she can do it for the rest of her life. She said some Canadian commissioners had warned her of fatigue from processing so many people's trauma, and it has already weighed on her.

But progress has come faster than she expected. NABS now has seven employees and is looking to hire more. A revised version of the Truth and Healing Commission bill is expected to be introduced in Washington shortly — this time, Diindiisi McCleave said, with more lawmakers ready to listen.

The coalition has partnered with University of Minnesota and the First Nations Repatriation Institute in recent years to conduct an anonymous survey called Child Removal in Native Communities that's expected to be completed next year. So far there have been submissions from about 900 tribal members from around the country. NABS hopes to share whatever research it can with any future commissions that might have the authority to get records through a court order.

Diindiisi McCleave said she thinks of the prayers and cries that must have gone up to the creator as children were separated from their families: "This is a spiritual movement. This is being led by the foundation of thousands, hundreds of thousands, of prayers."

On Friday, a large crowd gathered outside Little Earth, the Native American housing complex in south Minneapolis, for a vigil and march honoring boarding school survivors. Among the demonstrators was Jennifer Langreck, whose grandfather ran away in eighth grade from his boarding school on the Rosebud Indian Reservation in South Dakota and never returned. She has not asked him too much; she does not want him to relive those years.

"I'm going to walk three miles ... because he had to run even farther," Langreck said.

Diindiisi McCleave stepped onto the stage and told the audience about the coalition's work. Everyone there, she said, was marching to tell the truth.

"As we speak the truth about the horrors of colonization and genocide and we use our voice to demand justice for the millions of deaths on the battlefield or in the classroom, as we confront our perpetrators and understand our own pain, we heal — even just a little bit," she said.

The crowd filed across the park and began walking up Cedar Avenue, solemnly remembering what their ancestors endured.

maya.rao@startribune.com 612-673-4210