The Mounties are warning the public not to engage in road rage.
Sean McKenzie has been charged with first-degree murder.
Police said the Langley girl's death was an isolated incident.
RCMP are looking for the source.
Police say the dog was advertised for sale online.
All three were treated for injuries described as non-life-threatening.
The 13-year-old's body was found in a Burnaby, B.C. park.
The non-lethal multi-launcher fires pepper spray and rubber bullets.
Police found her partner's body and the couple's vehicle in the Mount Statlu Lake region.