Winnipeg police are preparing to search a massive landfill for the remains of a woman who may have been murdered by an alleged serial killer -- a task they estimate could take months, even a year, to complete.

Police will be searching the Brady landfill for the body of Tanya Nepinak, who has been missing since last September. She was 31 when she disappeared.

Investigators believe Nepinak was killed and her body dumped into a garbage bin that was eventually emptied into the landfill, located west of the city.

In June, 52-year-old Shawn Lamb was charged with second-degree murder in connection to Nepinak’s death.

Lamb has also been charged in connection to the deaths of two other women, 18-year-old Lorna Blacksmith and 25-year-old Carolyn Sinclair.

Blacksmith’s body was found in June behind an abandoned house, and Sinclair’s body was found inside a dumpster in March. Both bodies were wrapped in plastic.

All three women were of aboriginal descent.

Nepinak’s sister, Gail, told CTV Winnipeg she’s angry the bodies of the other victims were found while her sister is still missing.

“You know these other girls were found and then my sister gets hidden and you know like they throw her, throw her away like garbage,” she said.

Police are now setting up an area of the landfill that’s roughly the size of two football fields to begin their search. But before the search can begin, an excavation team must first dig out nearly a year’s worth of garbage from the site.

After the excavation team is done, police say a team of nearly 250 people will take part in the large-scale operation.

Winnipeg Police Chief Keith McCaskill told CTV Winnipeg that the sheer size of the search is daunting.

“This is something the Winnipeg Police Service has never undertaken before. We’ve certainly done searches on a smaller scale but this is a mammoth scale,” he said.

Investigators say the area of the landfill they will investigate is more than eight metres below the surface.

However, despite this challenge, McCaskill said the search will proceed.

“We are pleased to be able to say there’s an opportunity, or at least a chance, a slight chance of recovering something,” he said. “So we’ve got to take every step that we can to recover that for the family.”

Nepinak’s family had previously accused the police of failing to take action to find the woman’s body.

The family said they had been told the cost of searching the landfill would run up to $1 million because of the size of the search area.

“We take it as they’re not going to do anything,” said Gail on Tuesday. “We don’t want her left over there. She’s a human being. She’s my sister.”

The Nepinak family visited the landfill last week and while they are thankful that the search will soon begin, they say they cannot shake their anger at how long it has taken to retrieve Nepinak’s body.

“Being there and knowing that she was there amongst all that garbage really made me angry, just to think that nothing’s been done about it and that she’s been there for that long already,” said Nepinak’s ex-husband Vernon Mann.

With files from CTV Winnipeg’s Caroline Barghout and The Canadian Press