TORONTO -- Child welfare authorities realized they had files on a couple tasked with caring for a seven-year-old Toronto girl only after the child was found dead in the pair's apartment, a coroner's inquest heard Tuesday.

After learning of Katelynn Sampson's death from police on Aug. 3, 2008, the Children's Aid Society of Toronto searched its records and found Donna Irving had two children who became wards of the Crown, while Warren Johnson had been accused of sexually abusing his nieces, the organization's chief operating officer testified.

The agency convened senior managers to examine what services it had provided to the girl and her family and to "really make sense of this terrible tragedy that had befallen this child," Nancy Dale said.

They quickly discovered that some information had been lost in the transfer of information between CAS and its sister agencies, she said.

That prompted the agency to scrutinize its practices and eventually overhaul its referral and information-sharing practices, Dale said.

Among the changes that followed Katelynn's death was the creation of a uniform referral system shared by Toronto's four child welfare agencies, which also tracks whether the information has been received, she said.

Calls about Irving and Johnson were being referred to Native Child and Family Services because of Irving's aboriginal heritage, but had been handled by CAS before NCFS was designated as a child welfare agency in 2004.

A third agency, the Catholic Children's Aid Society, also received a call in early 2008 from a neighbour claiming that Irving was using crack and working as a prostitute, leaving Johnson -- who also had substance abuse problems -- to care for Katelynn and the couple's other children, the inquest heard.

The Catholic agency sent the information to a caseworker at CAS who had previously dealt with Katelynn, but the caseworker doesn't recall receiving it, Dale said.

The Children's Aid Society had been involved with Katelynn's mother, Bernice Sampson, between 1983 and 1995 because of her drug use. As a result, five of Sampson's children became wards of the Crown, she said.

The agency was called twice about Sampson in 2003, but found she was staying on the wagon and provided assistance on a voluntary basis for a few months, then closed her file in 2005, she said.

Irving had also had two children taken from her by CAS. Johnson didn't have a case file under his name, but he appeared in his sister's file and was accused in 1991 of sexually abusing his nieces, Dale said.

The agency felt it was able to verify the abuse against one niece, but did not add Johnson to the Child Abuse Register to spare the young, vulnerable girl from having to testify, Dale said. Police did not lay criminal charges, possibly for the same reason, she said.

That information was disclosed verbally to Native Child and Family Services when they started working with Irving and Johnson, but there is no record that NCFS requested a hard copy of the files, she said.

Katelynn came to live with Irving and Johnson in the spring of 2007 after her mother started using crack again. Sampson thought her daughter would fare better with the couple, who also had two young boys.

Instead, Katelynn was beaten for months and died of septic shock.

It was later revealed that a judge granted custody to Irving despite her criminal convictions for prostitution, drugs and violence. Johnson also had several convictions.

The couple pleaded guilty three years ago of second-degree murder in the girl's death and were sentenced to life in prison with no chance of parole for 15 years.

A handful of Toronto police incident reports involving the pair were also added as evidence at the inquest Tuesday.

The documents were requested in a notice of motion filed last week by the Provincial Advocate for Children and Youth, which argued the reports provide crucial information that will help understand the circumstances that led to Katelynn's death in 2008.

The reports "could form the basis for important recommendations," the advocate's lawyer, Freya Kristjanson, said in pushing for the documents to be included.

Most parties had expressed some support for the motion, although some raised concerns that including the reports would lengthen the inquest or broaden it beyond its original scope.