Quebec provincial police say an 82-year-old woman whose body was found east of Montreal died of knife wounds.
A 16-year-old boy has been charged with kidnapping, forcible confinement, auto theft and receiving stolen goods.
The teenager appeared briefly in court today and will remain in detention until his next appearance on Monday.
Rejeanne Pelletier-Charette was reported missing last Friday and her body was found about two kilometres from her home on Tuesday.
Police say autopsy results show she died of stab wounds.
Police have said there may be additional charges, including murder, after the evidence has been reviewed by the Crown.
Ms. Pelletier-Charette's damaged car was found in a shopping mall parking lot on Monday - the same day the teen was charged.
The accused cannot be identified because he is a minor.