Tuesday would have been Phoenix Sinclair's 13th birthday.

Instead, a public inquiry heard new details about how the young girl fell through the cracks of Manitoba child welfare even after a brutal beating ended her life when she was five.

Inquiry blog

Read the latest entries from the CBC's Katie Nicholson, who is covering the Phoenix Sinclair inquiry:

Her mother, Samantha Kematch, covered up the girl's death by telling people that Phoenix was living with relatives or in foster care, the inquiry was told.

In reality, the child had been buried in a shallow grave near a landfill after a deadly assault by Kematch and her boyfriend Karl McKay.

"They said that she was living with her dad," testified one witness, McKay's daughter, who cannot be identified under a publication ban.

"They told me that Phoenix got apprehended … [and was] in care," said another witness, a friend of Kematch, who also cannot be identified.

"We went to go visit [Kematch's] auntie once, and she asked where Phoenix was, and they told her that she was with [McKay's] sister," the second witness said later.

The inquiry is examining how child welfare failed to protect Phoenix, who had spent much of her life in foster care or with family friends before being returned to Kematch.

Apprehended shortly after birth

Phoenix had been seized shortly after her April 23, 2000, birth from Kematch and the girl's biological father, Steve Sinclair, because the young couple had histories of violence and were unprepared to care for her.

The inquiry has already heard that social workers frequently failed to keep tabs on Phoenix and would give her back to one or both of her parents without enforcing conditions such as parenting courses or addictions treatment.

An interval review, only portions of which have been made public for the inquiry, said that throughout Phoenix's short life, social workers provided a level of service that was "almost non-existent."

Social workers also failed to realize that Kematch's new boyfriend in 2004 was McKay, a man with an extensive history of domestic violence that is outlined in the province's family services database.

Two months before Phoenix's death in June 2005, two social workers acted on an anonymous tip that she was being abused and visited the family's Winnipeg apartment. They talked only to Kematch, who said she had company. They left without seeing Phoenix and closed the file.

The second witness testified Tuesday that Kematch admitted to lying about having company to keep the social workers outside the apartment.

"It would have been her and Phoenix home, but when they knocked at her door, she told them that she had company over so they wouldn't come in," the witness said.

Shortly after that visit, Kematch and McKay moved to a house on the Fisher River reserve. They neglected and abused Phoenix, sometimes shooting her with a BB gun and forcing her to eat her own vomit. She was often confined to the unfinished concrete basement.

McKay's son witnessed fatal attack

McKay's two sons were living in the home and one of them witnessed the 15-minute assault that killed Phoenix. It was McKay who delivered the final blows, the son testified earlier this week, and McKay and Kematch then wrapped up the girl's body in plastic and buried her.

The couple would continue to collect welfare payments with Phoenix listed as a dependent. Relatives believed she was living elsewhere.

Months later, one of McKay's sons told his mother that McKay had killed Phoenix. The woman called authorities. McKay and Kematch were arrested and eventually convicted of first-degree murder.

Right before her arrest in March 2006, Kematch tried one final deception. Social workers were demanding to see Phoenix because of the tip from McKay's former partner.

Kematch asked her friends if they knew a little girl she could borrow to pose as Phoenix.

"[Kematch] called me and asked me if I knew anybody that had a little girl about the age of five," McKay's daughter testified.

"I thought they were just committing some welfare fraud."

Kematch got a friend to lend her a daughter and met with the social worker. But the child did not play along with the ruse and Kematch was arrested.

McKay's daughter told the inquiry she had seen bruises on Phoenix on two occasions in 2004 — once on her head and once on an arm. Kematch and McKay said the bruises were caused by a truck accident and a fall in a bathtub, she said.

"It seemed legitimate. I have kids, too. They fall once in a while."

Tuesday marked the end of the first phase of the inquiry — the examination of Phoenix's case specifically. The inquiry will look next at improvements made since her death and, later, at the socio-economic issues that cause children to end up in care.

The inquiry started last fall and has been delayed a few times. Its overall budget is pegged at $9.6 million dollars.

Commissioner Ted Hughes, a retired judge, may deliver his report by the end of the year.