No agency will be held accountable in the death of a Camrose, Alta., mental health care worker killed on the job two years ago, CBC News has learned.

Valerie Wolski, 41, a caregiver working for the Canadian Mental Health Association, was strangled on Feb. 12, 2011.

Her client Terrence Saddleback, then 26, was charged with manslaughter, but was eventually found mentally unfit to stand trial.

OHS has two years from the date of an incident to decide whether to lay charges

Michelle Davio, a spokesperson for Alberta Justice and the Solicitor General, said that Crown prosecutors concluded there was no reasonable chance of conviction and proceeding with charges was not in the public interest.

"If there was any way to proceed with charges that would have satisfied the guidelines that the prosecution service uses, they would have done that," she said.

"Now the next step is to have a fatality inquiry and hope that maybe something can be learned through that process."

Saddelback, who is developmentally disabled, had been deemed dangerous to caregivers, but Wolski may never have been informed.

A 2009 risk assessment prepared after Saddleback attacked a female staff member at a group home in Wetaskiwin, Alta., warned that he could be so aggressive that he posed a threat to anyone, but especially women, who cared for him.

An Occupational Health and Safety report found that the provincially-funded program Persons with Developmental Disabilities (PDD) had failed to alert Wolski's employer about his violent history.

Saddleback was charged with manslaughter, but was eventually found mentally unfit to stand trial.

Changes made, minister says.

Craig Wolski told CBC News he has lost hope that his wife's death might change things.

He has lost faith in the provincial government and believes that politicians do not have the will to change the system.

Saddleback's legal guardian Graham Jones was devastated by Thursday's news.

“I don't want them to stand somebody and whip them or put them in jail for a hundred years, but at least tell me, ‘Yeah, I made a mistake,'" Jones said. "'And we'll try and prevent it from happening again.’”

Dave Hancock, the Human Services minister responsible for OHS, says changes were made and lessons learned after Wolski's death.

“This was a very tragic situation with dangerous circumstances and we will learn from the handling of this matter and make sure that it doesn't happen again," Hancock said. "And that's a very important way forward.”

With files from CBC's Janice Johnston