One year after her murder, Paula Gallant's sistersare knocking on doors in the hope someone can help catch her killer.

The 36-year-old Halifax-area teacherdisappearedon Dec. 27, 2005. Herbody was found hours later in the trunk of her car, which was parkedat the Timberleaschool where she taught Grade 3.

No one has ever been charged withher murder.

"Somebody murdered our sister, that's the biggest frustration," said Lynn Gallant-Blackburn, Paula's older sister.

"But also the fact that 12 months have passed and the monster responsible for the murder of our sister remains free."

Gallant-Blackburn and Lana Kenny spent Wednesday afternoon canvassing the Timberlea neighbourhood where their sister Paula lived, asking neighbours if they saw anything a year ago today.

Gallant last spoke toher sister around 1:30 p.m. on Dec. 27, 2005. She was reported missing hours later.

Just after midnight, a family member spottedGallant's green Chevrolet Cavalier parked outside Beechville-Lakeside-Timberlea Elementary School, near her home. Police arrived and opened the trunk.

Police have not said how Gallant died.

In the last year, police have made several appeals for information about the case. The Nova Scotia Department of Justice is offering up to $50,000 for information leading to a conviction.

Police now say they believe someone drove thecarto the parking lotat some point between 3:30 and6:30 p.m. and left it there.

"We either believe they left on foot or had avehicle waiting for them and they left in a different vehicle," said Const. Joe Taplin.

"Andthat's why we are trying to get people to think, if you were around the school area, do you remember seeing a different vehicle around here, do you remember seeing Paula's vehicle?"

Taplin said investigators have followed up on every lead that has come forward.

Gallant-Blackburn said every day has been frustrating and painful andshe'spleading with people tosearch their memories.

"They need to speak to their children andtalk to each other," she said. "Any piece of information they have is critical."