Under the Canadian Charter of Rights your child has the right to a lawyer if he or she is a suspect. Your child may need a lawyer and you may want to have the lawyer present when he or she is questioned.
Insist on having a support person present when the child is interviewed. This could be you or your spouse or partner or a family friend
Mennonite Central Committee Canada. (2011). Getting through the maze: A guidebook for survivors of homicide.