Nearly three weeks after the death of a senior intelligence officer in Afghanistan, the Canadian military remains silent on what happened, and friends of the officer fear they'll never learn how she died.

Maj. Michelle Mendes, 30, was found dead on April 23. (DND)

The body of Maj. Michelle Mendes, 30, was discovered April 23 in her living quarters on the military base in Kandahar.

Mendes, who was based in Ottawa with Defence Intelligence, was only days into her second tour of duty in the war-torn country.

Canadian Forces officials have said only that her death did not involve enemy action. The military has still not revealed the cause of death publicly and her family remains unaware of how she died, according to a military spokesperson in Kingston, Ont.

The Canadian Forces National Investigation Service, an independent unit, is handling the case.

Published reports have speculated about health problems or an accident, or possibly suicide. A military colleague of Mendes told CBC News, "None of us believe that."

Neither does Bill Patchett, a family friend who knew Mendes when she was young.

"I think that we have to wait and see what the outcome is," said Patchett. "I believe that we will never hear what happened. I really do."

Military colleagues and family alike were stunned by Mendes's death. At a May 2 memorial service in her hometown of Grafton, Ont., she was described as a bright and energetic person.

Rose quickly through intelligence ranks

Learning more about Mendes has proved difficult. Of the dozens of people contacted by CBC News who knew Mendes, Patchett was one of the few who would speak on the record, though a handful of others shared their thoughts privately.

"Once she got in the Armed Forces, she would never discuss it because it wasn't hers to discuss. It was quite confidential. And she was very good at keeping a secret," said Patchett.

Mendes, who had a master's degree in international affairs from Ottawa's Carleton University, rose remarkably quickly through the military ranks to become a major with the Chief of Defence Staff intelligence unit by the age of 30.

Her first tour of duty in Afghanistan in 2006 was cut short, though the reasons for that are still unclear.

Mendes's commanding officer declined to be interviewed, as did the chief of defence staff.

Instead, the office of the chief of defence staff referred CBC News to Capt. Jodi-Jane Longley, a friend of Mendes from military college who works at National Defence headquarters.

"It's tragic to lose anyone, anyone especially young in their career, someone as promising as Michelle," said Longley.

It's such promise that makes speculation about suicide hard to believe for Mendes's friends and colleagues.

But they say that without an explanation, it will be impossible to come to terms with her death.

With files from Krista Erickson