A 14-year-old Alberta girl convicted of murdering her family received the maximum allowable sentence on Thursday, which includes four years in a psychiatric institution.

The judge ordered the girl to undergo rehabilitative treatment during that time. She was also sentenced to 4½ years under conditional supervision in the community.

The girl killed her mother, father and eight-year-old brother in their Medicine Hat home on April 22, 2006.
(CBC)

The teenager was found guilty in July of three counts of first-degree murder for killing her mother, father and eight-year-old brother in their Medicine Hat home on April 22, 2006. She was 12 at the time.

The girl, labelled Canada's youngest convicted killer, was given credit for the 18 months she has already spent in custody, meaning she received the maximum sentence of 10 years. 

The girl received a rarely used type of sentence, known as the intensive rehabilitative custody and supervision sentence, meaning she will spend her first four years in a psychiatric hospital, instead of a youth detention centre.

To qualify for the sentence, which is set out under the Youth Criminal Justice Act, young offenders must be diagnosed with some form of mental disorder or emotional disturbance.

In his sentencing, Justice Scott Brooker said this was the most appropriate sentence for the girl, given the horrific nature of the case and her young age at the time the crimes were committed.

Brooker said it was difficult to conceive a more horrific crime. He said the girl, who cannot be named under the Youth Criminal Justice Act, had wonderful parents who loved their daughter and tried to get her into family counselling.

He described the murder of her eight-year-old brother as incomprehensible.

The lawyer for the girl argued for a sentence of three years incarceration, with most of that being at the psychiatric hospital.

The Crown prosecutor asked for a significantly longer incarceration time, arguing that the girl's pre-sentencing reports show she has an oppositional defiance disorder and conduct disorder.

"The young person does not recognize that she has committed a crime, nor does she have any insight into her condition," said prosecutor Stephanie Cleary.

The girl's ex-boyfriend, who is also accused in the killings, will also be in the Medicine Hat court on Thursday. He will be applying to have his trial moved to a venue in a larger city such as Calgary.

Jeremy Steinke, 24, faces three charges of first-degree murder.