TORONTO - At least 3,000 children, including four under the age of 10 found huddled together in frozen embrace, are now known to have died during attendance at Canada's Indian residential schools, according to new unpublished research.

While deaths have long been documented as part of the disgraced residential school system, the findings are the result of the first systematic search of government, school and other records.

"These are actual confirmed numbers," Alex Maass, research manager with the Missing Children Project, told The Canadian Press from Vancouver.

"All of them have primary documentation that indicates that there's been a death, when it occurred, what the circumstances were."

The number could rise further as more documents — especially from government archives — come to light.

The largest single killer, by far, was disease.

For decades starting in about 1910, tuberculosis was a consistent killer — in part because of widespread ignorance over how diseases were spread.

"The schools were a particular breeding ground for (TB)," Maass said. "Dormitories were incubation wards."

The Spanish flu epidemic in 1918-1919 also took a devastating toll on students — and in some cases staff. For example, in one grim three-month period, the disease killed 20 children at a residential school in Spanish, Ont., the records show.

While a statistical analysis has yet to be done, the records examined over the past few years also show children also died of malnutrition or accidents. Schools consistently burned down, killing students and staff. Drownings or exposure were another cause.

In all, about 150,000 First Nations children went through the church-run residential school system, which ran from the 1870s until the 1990s. In many cases, native kids were forced to attend under a deliberate federal policy of "civilizing" Aboriginal Peoples.

Many students were physically, mentally and sexually abused. Some committed suicide. Some died fleeing their schools.

One heart-breaking incident that drew rare media attention at the time involved the deaths of four boys — two aged 8 and two aged 9 — in early January 1937.

A Canadian Press report from Vanderhoof, B.C., describes how the four bodies were found frozen together in slush ice on Fraser Lake, barely a kilometre from home.

The "capless and lightly clad" boys had left an Indian school on the south end of the lake "apparently intent on trekking home to the Nautley Reserve," the article states.

A coroner's inquest later recommended "excessive corporal discipline" of students be "limited."

Acting Aboriginal Affairs Minister James Moore, speaking in Vancouver, called the deaths a "horrific circumstance" of the Indian residential school system.

"The residential school fact of Canada's history is a Canadian tragedy," Moore said.

The records reveal the number of deaths only fell off dramatically after the 1950s, although some fatalities occurred into the 1970s.

"The question I ask myself is: Would I send my child to a private school where there were even a couple of deaths the previous year without looking at it a little bit more closely?" Maass said.

"One wouldn't expect any death rates in private residential schools."

In fact, Maass said, student deaths were so much part of the system, architectural plans for many schools included cemeteries that were laid out in advance of the building.

Maass, who has a background in archeology, said researchers had identified 50 burial sites as part of the project.

About 500 of the victims remain nameless. Documentation of their deaths was contained in Department of Indian Affairs year-end reports based on information from school principals.

The annual death reports were consistently done until 1917, when they abruptly stopped.

"It was obviously a policy not to report them," Maass said.

In the 1990s, thousands of victims sued the churches that ran the 140 schools and the Canadian government. A $1.9-billion settlement of the lawsuit in 2007 prompted an apology from Prime Minister Stephen Harper, and the creation of the Truth and Reconciliation Commission.

The research — carried out under the auspices of the commission — has involved combing through more than one million government and other records, including nuns' journal entries.

The longer-term goal is to make the information available at national research centre.

Related on HuffPost:

Loading Slideshow...
  • A native dancer looks on during an 'Idle No More' gathering on Parliament Hill in Ottawa on Monday, Jan. 28, 2013. THE CANADIAN PRESS/Sean Kilpatrick

  • Native dancers rally during an 'Idle No More' gathering on Parliament Hill in Ottawa on Monday, Jan. 28, 2013. THE CANADIAN PRESS/Sean Kilpatrick

  • Idle No More Mall Protest

    <a href="http://www.huffingtonpost.com/social/LJ_Henshell"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/630755180/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/LJ_Henshell">LJ Henshell</a>:<br />A First Nations Drummer plays during a protest at Intercity Shopping Center in Thunder Bay, Ontario

  • It's about the future

    <a href="http://www.huffingtonpost.com/social/LJ_Henshell"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/630755180/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/LJ_Henshell">LJ Henshell</a>:<br />A child protests in Thunder Bay, Ontario

  • United we stand

    <a href="http://www.huffingtonpost.com/social/Doug_Cleverley"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/805699678/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Doug_Cleverley">Doug Cleverley</a>:<br />At the #IdleNoMore rally in Owen Sound (Saugeen Ojibway Nation territory), during a spontaneous round dance at the main downtown intersection.

  • Killer Whale Dance

    <a href="http://www.huffingtonpost.com/social/Courtney_Harrop"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/twitter_profile_img/4441016.png" /></a><a href="http://www.huffingtonpost.com/social/Courtney_Harrop">Courtney Harrop</a>:<br />Idle No More actions, Coast Salish Territories, Powell River, BC

  • Idle No More #J11

    <a href="http://www.huffingtonpost.com/social/Courtney_Harrop"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/twitter_profile_img/4441016.png" /></a><a href="http://www.huffingtonpost.com/social/Courtney_Harrop">Courtney Harrop</a>:<br />Coast Salish Territories, Powell River, BC

  • Idle No More #J11 March

    <a href="http://www.huffingtonpost.com/social/Courtney_Harrop"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/twitter_profile_img/4441016.png" /></a><a href="http://www.huffingtonpost.com/social/Courtney_Harrop">Courtney Harrop</a>:<br />Coast Salish Territories, Powell River, BC

  • Tla'Amin Prayer Song #J11 Idle No More

    Tla'Amin Prayer song on #J11 2013 Idle No More, Coast Salish Territories, Powell River BC

  • Tla'Amin Killer Whale Dance, #J11 #IdleNoMore

    Tla'Amin Killer Whale Dance, #J11 #IdleNoMore, Coast Salish Territories, Powell River, BC

  • C45 affects all Canadians! Join the fight.

    <a href="http://www.huffingtonpost.com/social/Eleanor_Kure"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/840875359/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Eleanor_Kure">Eleanor Kure</a>:<br />At the Idle No More protest in Halifax Nova Scotia. with an eco-justice article in pocket, spreading the word that Bill C45 affects every Canadian, not only First Nations. Thank you FN, for beginning this movement.

  • Piyesiw Awasis

    <a href="http://www.huffingtonpost.com/social/mizzren"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/twitter_profile_img/3183681.png" /></a><a href="http://www.huffingtonpost.com/social/mizzren">mizzren</a>:<br />Thunderchild First Nation @ Lloydminster Flash Mob. January 16, 2013

  • <a href="http://www.huffingtonpost.ca/2013/01/16/idle-no-more-queen-elizabeth-2-highway-blockade-alberta_n_2490009.html">Idle No More supporters jump onto a truck</a> as they are pushed by a driver trying to pass, as the protesters block Highway 2 as part of a planned national day of action, in Edmonton, Alberta on Wedneday January 16, 2013.

  • Aboriginal protesters march down Huron Church Road towards the Ambassador bridge in Windsor Ontario, Wednesday, January 16, 2013. About 1000 demonstrators disrupted traffic to the country's busiest border crossing for several hours.

  • Aboriginal protestors pray at the end of their blockade of a CN railroad track just west of Portage La Prairie, Man., on Wednesday, January 16, 2016. They ended their protest without incident.

  • Aboriginal protesters demonstrate at the base of the Ambassador Bridge in Windsor Ontario, Wednesday, January 16, 2013. About 1000 demonstrators disrupted traffic to the country's busiest border crossing for several hours.

  • Idle No More demonstrators block a CN east-west track just west of Portage La Prairie, Manitoba Wednesday, January 16, 2016.

  • Mississaugas of the New Credit support INM

    <a href="http://www.huffingtonpost.com/social/Vicki_King_Jamieson"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/750500023/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Vicki_King_Jamieson">Vicki King Jamieson</a>:<br />New Credit Youth supporting INM

  • Montreal Idle No More

    <a href="http://www.huffingtonpost.com/social/Caillum"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Caillum">Caillum</a>:<br />Thousands of people, both Native and Canadian, show their support at an Idle No More protest in Montreal on January 11th, 2013.

  • #Denendeh #J11 #IdleNoMore #YZF #NWT Yellowknife "Northwest Territories"

    Video of the Global Day of Action rally in downtown Somba K’e (Yellowknife)on the Akaitcho territory of the Yellowknives Dene First Nation in Denendeh (Northwest Territories).

  • #IdleNoMore March and Round Dance in Yellowknife Denendeh NWT

    "Today (Friday, December 21, 2012) in Denendeh and across the globe, we made an impact, a statement for true justice to be brought forward and acknowledged. But it will not stop, for the 8th fire has been lit and will only grow. Mahsi for all who showed up and united, we felt the support....we felt the fire!! And there's more to come in the new year." On Facebook By Lawrence Nayally, Melaw Nakehk'o and Eugene Boulanger https://www.facebook.com/events/112403725595655/

  • Attawapiskat Chief Theresa Spence, wearing a headdress, takes part in a drum ceremony before departing a Ottawa hotel to attend a ceremonial meeting at Rideau Hall with Gov. Gen. David Johnston in Ottawa, Friday January 11, 2013.

  • Attawapiskat Chief Theresa Spence, centre, departs a Ottawa hotel to attend a ceremonial meeting at Rideau Hall with Gov. Gen. David Johnston in Ottawa, Friday January 11, 2013.

  • Prime Minister Stephen Harper meets with First Nations leaders in Ottawa on January 11, 2013.

  • Prime Minister Stephen Harper meets with First Nations leaders in Ottawa on January 11, 2013.

  • Attawapiskat Chief Theresa Spence makes a brief statement on Victoria Island near Parliament Hill Friday January 11, 2013 in Ottawa. Spence is speaking out for the first time about how her reserve spends government money, saying most of what flows to her isolated James Bay reserve actually gets spent outside the community.

  • Aboriginal Chiefs stand at the main gate to Parliament Hill during a protest Friday January 11, 2013 in Ottawa.

  • Idle No More protesters listen to speakers during a rally on Parliament Hill Friday January 11, 2013 in Ottawa.

  • Gordie Odjig of Wikwemikong stands at the west gate to the Langevin Block during the aboriginal meeting in Ottawa on Friday, January 11, 2013.

  • Idle No More at UBC Vancouver

    <a href="http://www.huffingtonpost.com/social/Randall_Gray"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/100001602753648/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Randall_Gray">Randall Gray</a>:<br />

  • Idle No More at UBC Vancouver

    <a href="http://www.huffingtonpost.com/social/Randall_Gray"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/100001602753648/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Randall_Gray">Randall Gray</a>:<br />

  • Los Angeles Rally In Solidarity with First nations

    <a href="http://www.huffingtonpost.com/social/hp_blogger_Melinda Gopher"><img style="float:left;padding-right:6px !important;" src="http://www.huffingtonpost.ca/contributors/melinda-gopher/headshot.jpg" /></a><a href="http://www.huffingtonpost.com/social/hp_blogger_Melinda Gopher">HuffPost Blogger Melinda Gopher</a>:<br />Brock Conway, Blackfeet activist, with Saulteaux Actor Adam Beach and companion. Photo: Morning Star Gopher

  • Native protesters march up Wellington Street in Ottawa on Friday, January 11, 2013.

  • Four-year-old Phoenix Sky Cottrelle,from Aamjiwnaang First Nation, holds a sign as aboriginal protestors gather on Victoria Island before they march to Parliament Hill in Ottawa on Friday, January 11, 2013.

  • Aboriginal protestors hold signs as they march from Victoria Island to Parliament Hill in Ottawa on Friday, January 11, 2013.

  • Gordie Odjig, an aboriginal protestor from Wikwemikong, shouts as he marches from Victoria Island to Parliament Hill in Ottawa on Friday, January 11, 2013.

  • Woman's Voices

    <a href="http://www.huffingtonpost.com/social/Courtney_Harrop"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/twitter_profile_img/4441016.png" /></a><a href="http://www.huffingtonpost.com/social/Courtney_Harrop">Courtney Harrop</a>:<br />Idle No More event Dec 30th,2012. Tla'Amin Nation Coast Salish Territories Powell River, British Columbia.

  • Idle No More Edmonton

    <a href="http://www.huffingtonpost.com/social/AUPELOCAL6CHAIR"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/twitter_profile_img/4411530.png" /></a><a href="http://www.huffingtonpost.com/social/AUPELOCAL6CHAIR">AUPELOCAL6CHAIR</a>:<br />Planned overnight and what a turn out!

  • IdleNoMore March, Dauphin, Mb

    <a href="http://www.huffingtonpost.com/social/Phyllis_Racette"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1354341984/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Phyllis_Racette">Phyllis Racette</a>:<br />#IdleNoMOre Dauphin, Mb

  • Chicago Idle No More @ the Canadian Consulate

    <a href="http://www.huffingtonpost.com/social/Jolene_Aleck"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/644015258/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Jolene_Aleck">Jolene Aleck</a>:<br />Chicago's Idle No More 1.5.2012 rally @ the Canadian Consulate

  • VancouverC Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • A man waves a flags as aboriginal protesters and supporters in the Idle No More movement block the Blue Water Bridge border crossing to the United States in Sarnia, Ont. on Saturday, January 5, 2013.

  • VancouverA Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • VancouverB Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • VancouverD Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • VancouverH Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC, January 2, 2013.

  • VancouverF Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • VancouverE Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • VancouverG Jan 2 2013

    <a href="http://www.huffingtonpost.com/social/gerrybates"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/gerrybates">gerrybates</a>:<br />Idle No More at Waterfront Station, Vancouver, BC

  • Flag Planting

    <a href="http://www.huffingtonpost.com/social/seawaytoday"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/seawaytoday">seawaytoday</a>:<br />Akwesasne Idle No More att Cornwall, ON

  • Dec 21st 2012 Idle No More Ottawa: Berdine

    <a href="http://www.huffingtonpost.com/social/Gail_Chicky_Gallagher"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/535670179/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Gail_Chicky_Gallagher">Gail Chicky Gallagher</a>:<br />