Defence Minister Peter MacKay ordered military staff to investigate political opponents who assailed his use of a search-and-rescue helicopter, internal documents show.

Last September, the Conservatives were on the defensive following a CTV News report that MacKay had used the chopper for a pick-up from an exclusive Atlantic fishing lodge.

Among other critics, Liberal MP Scott Simms attacked MacKay over the incident, which led to accusations that MacKay had used the aircraft as a personal taxi service.

Now, documents obtained by the Toronto Star show that as the Conservative party publicly kicked into damage control, in private, they went on the offensive.

The emails show that Canadian Forces staff had been asked to pour through flight records to see if Simms had also taken any rides aboard military aircraft.

It turns out that Simms had indeed taken a flight on Jan. 17, 2011, according to emails, to witness two search-and-rescue training exercises.

"Found it," wrote Maj. Byron Johnson, in an email to Air Force headquarters.

The email then lays out how Simms "flew with the … crew for almost the whole day," and that a "fax is on the way."

The response from Air Force headquarters was: "Great work by the (squadron operations) staff on such short notice … just to give you a taste of life in Ottawa!!"

Simms, meanwhile, says that he was the victim of a witch hunt designed to incriminate him, with the Conservatives setting a dangerous precedent.

"They have a political operation growing in Ottawa. And yet they want the political operation to spread throughout the entire bureaucracy," he said.

On Friday, MacKay dodged reporters and wouldn't answer any questions about the latest chapter in the chopper saga.

Canada's top solider, Gen. Walt Natynczyk, did not comment directly on the allegations.

"Again, I'll see what the staff have, and I'll drill down on it if I need to," he told reporters.

MacKay has maintained that the July 2010 flight aboard the helicopter was part of an operational demonstration.

"After cancelling previous efforts to demonstrate their search-and-rescue capabilities to Minister MacKay over the course of three years, the opportunity for a simulated search and rescue exercise finally presented itself in July of 2010," a statement from MacKay's office said last year.

MacKay had even mulled legal action against MPs who suggested he lied about the ride aboard the search-and-rescue chopper.

The helicopter transported the defence minister from the fishing lodge to the airport in Gander, N.L., in July 2010.

Documents released last year showed that some Defence staffers predicted that the trip could be a public relations problem.

Another email suggested that a potential PR blunder be avoided by disguising the trip as a search-and-rescue exercise.

With a report from CTV's Richard Madan