The family of a northern Alberta woman who was stabbed to death after police failed to respond to her 911 call says the system has let them down once again after the man charged in connection with her death was set free.

On Thursday, Stanley Willier was found not guilty of second-degree murder in the death of his common-law wife, Brenda Moreside, in their High Prairie, Alta., home after the only evidence against him was thrown out of court.

Brenda Moreside in a family photo.
(Handout)

The evidence was contained in a three-and-a-half hour long interview in which Willier told police about a violent fight between Willier and Moreside, during which he somehow ended up with a knife.

He said in the interview: "I didn't even … know I used a knife until the next morning when I came home and checked her out."

Eventually, Willier told the officer, "It hit me like a Mack truck."
"When I realized, okay, what I did."

The Crown's case unravelled when Judge John Gill ruled the statements Willier made to police were inadmissible.

Gill ruled that the RCMP hadn't given Willier enough opportunity to have a lawyer present while he was being questioned. The Crown attorney plans to appeal the ruling.

'Everybody let her down'

For Moreside's children, it is the latest in a series of disappointments that started the night their mother died in High Prairie almost two years ago.

"The circumstances of my mom's death really piss me off, so much so that I haven't really dealt with the fact that my mom is gone," Moreside's daughter, Cynthia Flaata, told CBC News Thursday.

"I feel like, everybody let her down, like everyone, so I'm pretty upset."

Moreside's children are in the process of preparing a lawsuit against the RCMP for not showing up when their mother called 911.

As CBC News has revealed, Moreside had called 911 on Feb. 13, 2005 to report that her intoxicated common-law husband was trying to break into a window of their home.

She was told that police could not charge him with damaging his own property, and the RCMP did not dispatch a car to respond to her call.

Moreside's body was found in the house 12 days later. She had been stabbed several times.

An internal RCMP review later confirmed the case "falls within the guidelines that require police attendance to the source of the call."

Recommendations from the internal review included more comprehensive training of officers for domestic and child abuse cases.