The sentencing hearing for the mother of twin girls who were found seriously injured and neglected – one later died - in 2012 started Monday, with a victim impact statement from a social worker involved in the case.

The Edmonton mother, who cannot be identified to protect the identities of the children involved, sat motionless as the social worker described what she called the “worst case of neglect and mistreatment” she had seen in her entire career.

“We could never have prepared for such a horrendous case,” social worker Sheli Steil told the court.

Steil talked about ‘Baby M’, the twin daughter who died in September, 2012, and everything the child would miss due to her parents’ actions.

“…took away a lifetime of experiences for her. She will never go to school and enjoy friendships…” Steil said.

“She will never know the joy of simply living,” Steil continued.

Steil’s statement went on to talk about ‘Baby S’, the twin who survived, and how her sister’s death would cast a shadow over her life.

“[She] will grow up with few memories of their sister. They will never know the person she will become,” Steil said.

“[Baby S] will face the knowledge that her parents provided for her brother, but not for her and her sister…”

On May 25, 2012, Edmonton police and paramedics were called to a south side home – officers arrived to find two-year-old twin girls, one was in cardiac arrest and suffering from a serious head injury, the other suffering from numerous other injuries.

Both were rushed to hospital, the child in cardiac arrest was revived, but had to be placed on life support in hospital.

Doctors found the twins were severely malnourished; one weighed nearly 6 kilograms (13 lbs.), the other just over 8 kilograms (16 lbs.).

The parents, who also had a son who was found in good health, were charged with aggravated assault, criminal negligence causing bodily harm and failing to provide the necessities of life.

Those charges were changed months later, when Baby M, was taken off of life support and passed away – two of the assault charges were changed to second degree murder.

In mid-July of 2014, the mother pleaded guilty to manslaughter, failing to provide the necessities of life for both girls, and a count of aggravated assault.

The father pleaded guilty to manslaughter, and was sentenced to 15 years behind bars in June, 2014 – at the time; he had 12 more years of his sentence to serve.

At the start of the hearing, the Crown Prosecutor addressed the tragedy of the case.

“Every once in a while there comes along a crime that is so horrific that a person with any kind of empathy cannot fathom, this is one of those cases,” the Crown Prosecutor said.

The Crown is asking for a sentence of 23 to 25 years in prison, due to the nature of the offences. The sentencing hearing is expected to continue all week.

With files from Kelsey Nichols