The stonewalling, they say, flies squarely in the face of government's legal obligations under a lawsuit settlement that saw Prime Minister Stephen Harper make an historic apology to First Nations for the residential school system.
"I'm astounded as to why the federal government in 2013 would find it convenient to stand on the side of the pedophiles and sadists who brutalized these children," New Democrat MP Charlie Angus told The Canadian Press.
"These aren't allegations. This was a massive police investigation with evidence and court transcripts."
At issue are records related to St. Anne's residential school in Fort Albany, Ont., which operated from 1904 to 1976.
An extensive Ontario Provincial Police investigation in the 1990s involving interviews with more than 700 people uncovered severe abuse that included use of an "electric chair" and ill children forced to eat their own vomit.
Several supervisors at St. Anne's in the 1960s and 1970s were criminally convicted.
Aboriginal Affairs Minister Bernard Valcourt has maintained the feds cannot release the voluminous documentation related to the criminal investigation for privacy reasons.
Valcourt's spokeswoman, Erica Meekes, called on Angus to apologize for his "outrageous and appalling" comments.
"Addressing abuse such as this is the reason our government set up the independent assessment process in the first place," Meekes said in an email.
"We will continue to ensure that the department fulfills its obligations under the Indian residential schools settlement agreement."
St. Anne's victims argue they need the material to help corroborate their abuse claims under the independent assessment process set up as part of the residential school settlement.
Fay Brunning, an Ottawa-based lawyer who acts for some of the St. Anne's claimants, said the government has had those records since 2003, and its failure to turn them over amounts to contempt of court.
"They don't want all these people who were forced to eat their vomit at St. Anne's to get paid," Brunning said from Timmins, Ont.
In July, Valcourt said the courts should decide what the government should disclose. A hearing is slated for Dec. 17.
Now, the Truth and Reconciliation commission set up as part of the residential schools settlement is seeking to join the court battle.
"These materials are relevant to the mandate of the commission," according to the application to Ontario Superior Court filed last week.
"They document a five-year investigation of serious sexual and physical abuse of former students at the St. Anne's residential school which resulted in Criminal Code convictions."
The filings also show Justice Murray Sinclair, head of the commission, wrote the government on several occasions starting in May last year to ask for records relating to investigations and prosecutions concerning all Indian residential schools.
Initially, the government did not respond, but said last month it would not comply with the request.
"What does this apology and promise to deal fairly with these families mean if the federal government knew all along and decided that they would rather cover up?" Angus said.
In an August letter to Valcourt, Angus accused the minister's staff of lying to victims.
"They stated there was no documentation regarding abuse at St. Anne's," Angus said in his letter.
"Your staff provided the survivors a false narrative and in doing so, undermined their rights and compromised the process."
The commission, which has been in a long-running battle with the government over the wider issue of document disclosure, is required to complete its mandate by July 1, 2014.
Despite an earlier court ruling over document disclosure in its favour, the commission fears the government is trying to run the clock down.
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