HALIFAX -- Opposition leaders in Ottawa and Nova Scotia are calling for further investigation into why the RCMP destroyed potential evidence in the criminal proceedings against a Halifax man who was wrongfully convicted of murder.

Federal NDP Leader Jagmeet Singh says an outside probe is needed to examine why an RCMP investigator's research on other suspects was destroyed in the lead-up to Glen Assoun's unsuccessful 2006 appeal.

"Techniques employed by police in this case are very concerning and raise questions about how fairly the accused are treated in our criminal justice system," Singh said in an emailed statement.

Assoun was convicted in 1999 of the knifing murder of Brenda Way four years earlier. He spent almost 17 years in prison and over four years on bail before being exonerated earlier this year.

Singh is calling on Public Safety Minister Ralph Goodale to "immediately order a review of this case to figure out what went wrong."

Green party Leader Elizabeth May says an inquiry should probe the "disturbing" destruction of potential evidence prepared by Const. Dave Moore, an analyst in an RCMP unit that looked at the behaviour of serial offenders.

Federal Conservative leader Andrew Scheer's office said he has no comment because there may eventually be a lawsuit, and Goodale declined an interview.

On Tuesday, Nova Scotia Justice Minister Mark Furey was cleared by the province's conflict of interest commissioner to review the file, despite the cabinet minister's 32-year career as a Mountie.

Furey issued a statement saying, "I will now review this matter in detail and consider next steps in consultation with my federal colleagues."

Meanwhile, the leader of the provincial Progressive Conservative Party in Nova Scotia, Tim Houston, is also calling for "an investigation of some sort," while Gary Burrill, the leader of the provincial NDP says an independent inquiry is needed.

"We need to understand what went wrong," Houston said in an interview. "Whether that raises to the level of public inquiry or not, I'm not sure. But I'd want to see an independent investigation to see what went wrong and how to prevent this from happening again in the future."

A federal Justice Department report made public on July 12 revealed that the RCMP erased and disposed of Moore's theories of other suspects -- including multiple murderer Michael McGray -- in the Brenda Way case.

The federal report also says McGray has denied killing Way.

The department's preliminary assessment, which led to Assoun's release in 2014, was released after an application by The Canadian Press, the CBC and the Halifax Examiner.

It says Assoun's lawyer sent several notes to the Crown in the fall of 2004 that specifically asked for disclosure of police files about McGray and statements from McGray's former girlfriend.

His lawyers also asked for information about McGray from the Violent Crime Linkage Analysis System, or ViCLAS -- a national database that makes links between cases based on the behaviour of violent murderers like McGray.

They did not know -- as the preliminary assessment has now revealed -- that Moore had gathered a large amount of material, from both the ViCLAS system and more conventional investigations.

Moore is quoted in the federal report saying he was able to place McGray in the immediate area where Way worked and lived by analyzing where the serial killer received his welfare cheques in 1995.

The RCMP investigator also exchanged personal correspondence with McGray and says he assessed his psychiatric reports.

An RCMP inspector's 2014 internal review of why Moore's files were destroyed or disappeared -- which was also released on July 12 -- says ViCLAS analysis "has never been introduced as evidence in criminal proceedings in court."

It also says that while Moore provided suspects, "it is not possible for ViCLAS analysis to conclusively establish any of them committed the homicide or that Assoun did not."

However, a retired Mountie who worked with Moore said in an interview Tuesday he reviewed his colleague's work before it disappeared and found it credible.

Gilles Blinn said that while the former colleague wasn't well liked by his superiors, he felt the analysis Moore prepared on McGray "was excellent work on his part."

"The research (in ViCLAS) is absolutely not to be tampered with," said Blinn.

Assoun's lawyers, Sean MacDonald and Phil Campbell, wrote in an email that "the RCMP commissioner and the Halifax chief of police should be demanding to find out how critical evidence of Glen's innocence was suppressed and destroyed so they can tell the public."

"Basic questions have not been answered. At this point, silence amounts to collaboration," they wrote.

The RCMP has said in an email that the destruction of Moore's files ran counter to the force's policy, but it added this was not "malicious."

MacDonald and Campbell have said they believe Assoun should receive compensation in the short term as he is living "hand to mouth, depending on the kindness of strangers."

Assoun has said that while he was in prison he suffered multiple heart attacks, developed mental illnesses and suffered a severe beating that led to a broken leg.