A much-anticipated public inquiry into the 2005 death of five-year-old Phoenix Sinclair has begun after years of legal wrangling, with the commission counsel saying she hopes the little girl's life and death will serve as a catalyst for change.

"How is it that in our society, a small child can become so invisible … to an entire community, one which includes social service agencies, schools, neighbours, friends and family? So invisible as to literally disappear?" Sherri Walsh told the inquiry Wednesday.

Walsh displayed several photographs of Phoenix and told those assembled to keep the pictures in mind during the hearings.

The inquiry, first called by the Manitoba government in 2006, at circumstances surrounding the death of Phoenix, a five-year-old girl who had been neglected and repeatedly abused by her biological mother and stepfather.

The probe, formally constituted more than a year ago, had been delayed by legal wrangling and pre-inquiry motions, and by the criminal trials of her mother and stepfather.

Samantha Kematch and Karl McKay were both convicted of first-degree murder in 2008.

The first witness to testify on Wednesday was Alana Brownlee, the current chief executive officer of Winnipeg Child and Family Services, who described the mandate and powers of Manitoba's child welfare agencies.

Brownlee said there was a growing workload in the foster care system at the time and that new policies were being put in place that required workers to perform more tasks for every family they served.

Child was neglected, abused

Phoenix was killed on the Fisher River First Nation in June 2005, but it was not until nine months later that her body was found wrapped in plastic in an unmarked shallow grave near the community's landfill.

Court heard during the trial that the pair neglected, confined and repeatedly beat Phoenix.

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Phoenix Sinclair in an undated photo released at Manitoba's public inquiry, Sept. 5 2012. (Phoenix Sinclair inquiry)

The child was apprehended by Child and Family Services (CFS) at least twice — once at birth and again three years later — but she was returned to her mother each time.

Child welfare workers closed Phoenix's file in early 2005, just a few months before her death. One social worker had gone to check on her and was told she was asleep. The worker saw a sibling playing outside who appeared healthy and left.

According to evidence at the murder trial, Phoenix was frequently confined, shot with a BB gun, forced to eat her own vomit and neglected.

She was killed in the basement of the family's home on the Fisher River reserve and buried near the landfill. Her mother continued to claim welfare benefits with Phoenix listed as a dependent.

Exploring broad social issues

The inquiry hearings are scheduled to run for three months and will look at how Manitoba's CFS officials handled Phoenix's case and why her death went undiscovered for months.

The inquiry will also explore some broader social issues, including why aboriginal children account for approximately 8,000 of the 9,000 Manitoba children in foster care.

"I hope it brings them some kind of peace of mind," Jeff Gindin, a lawyer representing Phoenix's biological father and her foster mother, told CBC News before the inquiry began.

"I mean, you can't ever deal with what they lost. Nothing's going to help them get over that. But part of the problem is not knowing what happened exactly."

Walsh said she has corresponded with Kematch and McKay, but neither was willing to participate in the hearings.

Walsh said she ultimately decided that hearing from the pair would not further the purposes of the inquiry.

In July, inquiry commissioner Ted Hughes rejected the idea of a ban on publishing the names of social workers involved in the case, as was proposed by their union.

With files from The Canadian Press