Winnipeg police believe the driver of a gold-coloured car could "hold valuable information" about the 2015 disappearance and homicide of Thelma Krull.

Four years to the day after the Winnipeg grandmother mysteriously vanished while out for a walk, police said Thursday they recently received a tip about someone who might have seen Krull's last moments.

"We have learned of an individual who may hold valuable information about Thelma's disappearance. This person, who was in a position to observe Thelma, may not yet realize that they saw or heard something of value and for that reason, we want to speak to them," police spokesman Const. Jay Murray said.

"This individual is a driver of a gold-coloured four-door sedan."

Murray said police don't have a description of the driver but believe the car is a 2005-2010 import, such as a Toyota, Hyundai or Honda.

Despite thousands of hours of investigative work by both the Winnipeg police and the RCMP, Krull's homicide remains unsolved.

"That said, the answer is still out there, and we are confident that a member of our community can help us," Murray said.

Several pieces of evidence, including Krull's glasses and cellphone, were found on the ground by Kimberly Hill, in the park behind Kildonan-East Collegiate. (Winnipeg Police Service)

Police are urging anyone who knows of that vehicle, or any other information about Krull, to call 204-986-6508.

The 57-year-old woman left her Winnipeg home just before 7:30 a.m. on July 11, 2015, to go for a walk — part of her training to eventually hike the West Coast Trail in British Columbia.

She was never seen again, despite numerous searches.

She is believed to have walked from the Grassie Boulevard area to Kimberly Hill, in the park behind Kildonan-East Collegiate, where she arrived around 8 a.m. Police pieced those times together based on security cameras at homes Krull walked past.

Several pieces of evidence, including Krull's glasses and cellphone, were found on the ground by the hill. Police say those are signs Krull was in distress and they believe she may have been abducted.

It wasn't until Oct. 27, 2018, that a hunter came across her remains in a wooded area near Chemin Perrin Road in the rural municipality of Taché​, southeast of Winnipeg.

DNA testing later confirmed the remains were Krull's.

In July 2017, police released these sketches of a possible suspect in Krull's disappearance. (Winnipeg Police Service)

Police have received numerous tips from the public in the years since Krull disappeared, including from witnesses who said a woman matching her description was seen with a heavy-set man in the area of Kimberly Avenue and Grey Street and appeared to be in distress.

They later released sketches of a possible suspect and urged anyone with information about him, or possible sightings of Krull in his company, to contact them.

On Thursday, Murray said police don't believe the person in the sketch is connected to the gold-coloured car.