The federal government will not re-appoint the chairman of an embattled military watchdog agency, The Canadian Press has learned.

Peter Tinsley has been told his leadership with the military complaints commission will be allowed to expire and it will likely end before a probe of Afghan prison torture is completed.

Defence Minister Peter MacKay wrote to Tinsley, a respected former international war crimes prosecutor in Bosnia, that his position will not be renewed; he'll be replaced when his term comes to an end on Dec. 11.

The termination date is well before any resolution to the often-delayed public interest hearings into allegations that Canadian military police knew — or should have known — that some of their Taliban prisoners handed over to local authorities faced possible abuse in Afghan jails.

A spokeswoman for the commission confirmed the existence of the Sept. 9 letter from MacKay but declined to release it, citing the national security contents of some of its passages.

"What I can tell you is that the chair is committed to proceeding with the hearings," Nancy-Ann Walker said. "However, it's not certain there will be enough time to deliver a report before his current term expires."

Walker did not explain why news of Tinsley's departure had been kept under wraps, but defence sources claim the commission has been arguing behind-the-scenes over the decision.

Delaying tactics

The watchdog was supposed to resume a public hearing Monday. But proceedings were postponed until Wednesday after federal lawyers bombarded the agency with a series of motions demanding further delay and questioning, among other things, the jurisdiction of the commission.

Tinsley was not available to comment about his impending departure.

A spokesman for MacKay, Dan Dugas, said no commission chair has ever been re-appointed.

"He was told last month his term was up in December and we thanked him for his service," Dugas said in an email.

But a legal expert said it is a well-established practice with independent federal commissions, such as human-rights tribunals and quasi-judicial panels, to grant extensions to members whose terms end during lengthy investigations.

Errol Mendes, a University of Ottawa legal expert, called MacKay's decision an attack on the commission, which Tinsley has led since being appointed by the Liberals in 2005.

Tinsley's departure not only puts in jeopardy the commission's Afghan investigation, it also places the whole system of arm's-length agencies at risk, Mendes charged.

Tinsley has been embroiled in "legal trench warfare" with lawyers in the federal Justice Department since announcing his intention to pursue the prisoner transfer investigation.

Mendes accused the department of using delaying tactics in order to deliberately run out the clock on Tinsley's term, aiming to undermine the investigation or appoint a chair less familiar with the case.

"This raises a huge, huge systemic issue," Mendes said. "Is it legal or constitutional to stymie legal and administrative tribunals in this way? Because if it can be done to this commission, it could be done in any administrative tribunal in this country and that calls into question the fundamentals of administrative justice."

Cries of political interference

In the Commons last week, MacKay insisted the Conservatives were not trying to obstruct the Afghan probe and had provided dozens of witnesses and hundreds of pages of documents to the commission.

He said the department's actions were prescribed by either the National Defence Act or the Canada Evidence Act.

"This is not politically motivated," MacKay said Thursday. "There is no political interference."

The Conservatives were under attack last week over government lawyers' attempts to get Canadian diplomat Richard Colvin stricken from the witness list for the public inquiry. Colvin has signalled he has information about torture in Afghan prisons.

Government lawyers argued that a recent Federal Court decision limits the scope of the inquiry to what military police knew — or should have known — and that Colvin's testimony would fall outside that test.

They made the declaration without knowing what information Colvin might possess and wrote to his lawyer last week asking for information about the nature of his possible testimony.