TORONTO -- A seven-year-old Toronto girl fatally abused by her guardians would have been in severe -- and noticeable -- pain for some time after being struck so hard that her liver ruptured, the inquest into her death heard Tuesday.

Katelynn Sampson's autopsy showed a piece of the organ had completely detached and migrated to her pelvic area, the forensic pathologist who examined her body said.

"I've done a lot of autopsies...I've never seen this phenomenon before. I've never heard of this phenomenon before," Dr. David Chiasson testified.

It would take a "very, very significant amount of force" to cause such damage, he said, adding that liver injuries are sometimes seen in victims of car crashes.

Katelynn also suffered several rib fractures, bruises and lacerations on her face and limbs in the weeks and months before her body was found on Aug. 3, 2008, he said.

Autopsy photos presented at the inquest showed she had a black eye, her body was swollen and she had significant pooling of blood in her lower back.

There was also scarring on her heart, which is "very unusual for a seven-year-old," but that was probably a complication of her other injuries, the pathologist said. There was no evidence of a brain injury or sexual assault.

The bruises on her face "would have been evident" to others, and it would have been clear from Katelynn's behaviour that she was in severe -- possibly excruciating -- pain, Chiasson said.

But none of her injuries would have been fatal had she received medical treatment, and the complications from those injuries killed her, he said. Shock and bacterial infection, likely stemming from a deep laceration on her finger, were among the causes, he said.

Katelynn's last visit to the doctor was in the fall of 2007, when she was already living with her guardians, Donna Irving and Warren Johnson, though they had not yet obtained custody, the lead investigator in the case testified.

Investigators initially believed Katelynn's injuries were inflicted the night she died, but realized after the autopsy they were dealing with ongoing abuse, Toronto police Det.-Sgt. Hank Idsinga said.

After the pair's arrest, some friends and relatives told police they had noticed Katelynn's bruises and her change in demeanor, but none had reported it to child protection services, he said.

Nor had any of them alerted authorities that Irving was using crack cocaine and Johnson was consuming up to 12 beers a day, he said.

At no point did the court that granted the couple custody hear about their criminal records or Irving's lengthy involvement with child welfare agencies, or that her two older children had become wards of the Crown, Idsinga said.

By the time they officially became Katelynn's guardians in June 2008, the girl had missed months of class and her school had called children's aid three times, the inquest heard.

Paramedics found Katelynn's battered body in the Toronto apartment where she lived with the couple and their two sons after Irving called 911. One of the paramedics who attended the scene previously testified she believed Katelynn had been dead for some time.

On the early morning call, which was played at the inquest Monday, Irving could be heard sobbing as she told the operator the girl had choked to death on bread.

Irving and Johnson 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.

Katelynn's mother, Bernice Sampson, was addicted to crack and gave her daughter to Johnson and Irving in a misguided attempt to save Katelynn.