It's been a decade since 70-year-old Stephanie Stewart vanished while working alone at a wildfire lookout in dense mountain forest in northwestern Alberta.

RCMP determined the healthy and adventurous senior, an experienced fire spotter who spent many summers living in the bush, was most probably a homicide victim.

Spokesman Cpl. Hal Turnbull says tips continue to come in about the case, but there have been no arrests.

Her body has never been found.

"It's a very puzzling thing," Turnbull says.

"We're moving forward the best we can on what we have. Some cases are more difficult than others. And this is just a very difficult case."

The search for a killer

It was a sunny Saturday morning on Aug. 26, 2006, when Stewart was reported missing.

The woman, who had spent the last dozen summers working at a lookout near Hinton, had last talked with a family member the night before. When she failed to make her scheduled radio check-in for work that morning, another fire spotter was sent to her lookout to see if she was OK.

She was gone.

A pot of water had been left boiling on the stove and her truck was still parked outside.

Some items were missing from her cabin: two pillows with blue covers, a burgundy bed sheet, a Navajo-patterned duvet and a gold watch.

Turnbull says forensic evidence and other information gathered during the early days of the investigation led officers to rule out that Stewart was attacked by a animal, died in an accident or suffered a medical episode that caused her to wander away.

They concluded she was killed by someone.

Marc Symbaluk, a volunteer with Hinton Search and Rescue, managed the initial search for Stewart. It was one of the largest undertaken in the province, he says, and the group remains ready to help investigators if it gets the call.

"Stephanie has a special place in my heart," says Symbaluk, who adds that from the back deck of his home he can see the lookout tower where Stewart worked.

He thinks of her often, he says.

Stephanie's legacy

There are 127 fire lookouts in operation in Alberta. The provincial government added safety features to them after Stewart disappeared.

Signs that used to point visitors toward popular lookouts have been taken down. Lookouts with road access now have locked gates. Staff are also trained in self-defence and are equipped with hand-held radios with panic buttons.

Dennis Malayko with the Alberta Union of Provincial Employees says he's received no complaints from lookout workers since Stewart was killed. But he hadn't had any complaints before then either.

"I'm hearing they feel safe," Malayko says.

"Stephanie — I give her this legacy — it's a terrible thing that happened, but as a consequence there was some very positive measures taken."

Friend Robin Slater says Stewart, who was from Canmore, Alta., was a phenomenal woman who cycled solo across Canada and climbed Mount Kilimanjaro. But her perfect place was the lookout, where she tended a huge garden, embroidered, painted and read stacks of books.

Former government forestry worker Bob Young remembers Stewart as a kind and gentle soul, who welcomed the many visitors who came to her lookout.

Young retired a few years before Stewart vanished, but before that had stopped often to see her as he sketched maps and took photos of all the province's lookout areas.

He hopes reminding the public of her case will trigger someone's memory and finally solve the mystery.

"There's someone out there who knows."