WINNIPEG - A woman who, as a child, witnessed her mother kill her father is now preparing to go to prison for killing her young daughter.

The chilling tale of multi-generation family violence is playing out in a Winnipeg courtroom, and is likely to raise more questions about Manitoba's troubled child welfare system.

The woman, now 29, had worked as a prostitute and was addicted to crack cocaine. She had her three children taken from her by Child and Family Services.

In 2009, she regained custody of her toddler as she entered an aboriginal women's shelter that offers parenting courses and other supports. But she became violent with the young girl, and one night in June, she held her hand over the girl's mouth until she stopped breathing, court was told.

She then placed the child back in her crib and put a blanket over her. She did not tell anyone about what happened except her boyfriend -- via telephone, because he was in jail. The boyfriend called the shelter and told them what happened.

Autopsies would later reveal dozens of bruises on the girl's body and bites on her legs. Some bruises were old, some were still forming when she died.

It was "gratuitous violence", according to Crown attorney Colleen McDuff, who asked the court Monday for a 12-year sentence.

"There is a degree of anger, malevolence, that is difficult to explain," McDuff said.

The woman pleaded guilty last year to manslaughter but has failed to show any remorse, McDuff said.

The woman addressed the court briefly Monday. She did not apologize for the death, but instead criticized the support services offered at the shelter.

"Every time I did ask the staff for help, there was no one there to help me," the diminutive woman said in a soft voice.

Defence lawyer Steven Brennan said the woman is unable to show remorse because she suffers from post-traumatic stress disorder after a horrific childhood and a series of abusive adult relationships.

At the age of nine, she saw her mother kill her father, Brennan said.

"She remembers seeing a lot of blood," he told the court.

She was put into foster care and was sexually abused at age 11, he said. Later, she turned to prostitution to make money and became addicted to alcohol and crack cocaine. The trauma has left her unable to show emotion, Brennan said, even when she feels deeply remorseful.

"This is a horrible background. Simply horrific circumstances," he said.

Brennan asked for a sentence of five to six years, minus double credit for the time she has spent in custody since her arrest.

Chief Justice Glenn Joyal of Court of Queen's Bench has reserved decision on her sentence until mid-April.

He frequently challenged the defence's assertion that the woman deserved sympathy, and pointed to evidence that showed the woman did not participate in support programs at the shelter.

"She suffered more than most human beings should ever have to contemplate ... but at a certain point, she was given advantages," Joyal said.

"She declined the very support offered to her."

Joyal also pointed to Child and Family Services' decision to give the woman back her child "at a time when she probably ought not to have had any child near her."

The toddler's death is the latest example of a child welfare decision that has ended in tragedy.

The most notorious case was that of Phoenix Sinclair, a five-year-old girl who spent most of her life in foster care and was killed after being returned to her mother Samantha Kematch. Sinclair's death went unnoticed for months. Kematch and her boyfriend, Karl McKay, were later convicted of first-degree murder.

In another case, two-year-old Gage Guimond was removed from a foster home and given to his great-aunt, Shirley Guimond, despite the fact she had a criminal record. The boy was beaten and died after falling down stairs.

The Manitoba government has announced plans to hold a public inquiry into the Sinclair case.