A teenager has been sentenced to three years in detention and three years of supervised reintegration into society for the murder of another teen, much to the dismay of the deceased girl's family.

"He was laughing and laughing. After all he did to my daughter--what kind of justice is this?" asked

The boy, who cannot be named, pleaded guilty to the death of Francesca St. Pierre, 14.

Her body was found near a bike path on Aug. 19, 2007 in Riviere Des Praries. She had gone missing Saturday, Aug. 18 from her group home. She suffered from Tourette's syndrome and had to take medication several times a day.

The court heard she was beaten to death with a baseball bat after being lured out to the wooded area near the bike path.

The day after her body was found, Police arrested a 15-year-old boy who lived in the same group home for troubled teens.

He admitted in court that he wanted to "get rid" of Francesca. He also suffers from a mental illness.

He was first diagnosed with mental problems at the age of two. When he was five, his mother killed herself after killing his little sister. At the age of seven, his father was deported from Canada due to a criminal record, and he has been a ward of the youth system since.

He has been diagnosed with Tourette's syndrome, ADD, Bipolar disorder, is highly narcissistic and takes anti-psychotic drugs.

Guards at the court house said the boy may have been laughing and smiling during the sentencing because he was highly medicated.

Francesca's mother told CTV Montreal that she had complained to youth protection about the boy because he would ask Francesca for sexual favours.