A Winnipeg mother is set to mark her third Christmas without her two children.

They were taken by their father in summer 2008.

For the first 12 months after her kids were taken, Emily Cablek would walk past her children's old playground, just to watch their classmates play.

"Just to hope (my kids will) be back playing with them soon - just to keep the memories that I had," she said.

In August 2008, Dominic, age seven, and Abby, age five, vanished. Police said they were abducted out of the country by their father, Kevin Maryk, who didn't return them from a parental visit.

"The biggest part of me is missing…I can't get that back in my life. I can't fill that with anything," said Cablek.

Holidays, such as Christmas, are especially difficult, she said. Cablek can't bring herself to set up a Christmas tree.

"This is a case that really tugs at your heartstrings," said Det. Sgt. Shaunna Neufeld.

Investigators believe Maryk may be in the company of his nephew Cody McKay and friend Robert Groen. Both Groen and Maryk have criminal records.

Groen has outstanding charges for drug trafficking.

Maryk's record goes back to 1994, with convictions for assault, harassing phone calls and theft.

Sources told CTV News all three men have ties to an outlaw biker gang, connections that could make it easier to access passports and cash.

Officers would only confirm they're concerned for the children's well-being.

"We have strong concerns for their safety and concerns for who he associates with as well and the impact that has on the children," said Det. Sgt. Shaunna Neufeld.

Police have created a new YouTube video to try and gather tips from outside Canada's borders.

It's available to view online at:

http://www.youtube.com/watch?v=4byi5r2qeng 

Cablek and officers hope those with information will come forward about the children.

"They are always in my heart. I am always looking for them. I will never stop looking for them," said Cablek.

Anyone with information is asked to call Crime Stoppers at (204) 786-8477 or 1-800-222-8477, or the missing persons unit at (204) 986-6250.

Cablek is also hoping to hire a private investigator to help with the search. She's started a trust fund to help cover the costs. Anyone wanting to donate can do so at TD banks, with the trust fund listed under the names of Emily Cablek, or Abby and Dominic Maryk.

- with a report from CTV's Stacey Ashley