Vigils have been held nationwide in memory of 15-year-old Noongar and Yamatji boy Cassius Turvey, who died after he was allegedly attacked while walking home from school with friends in Perth. A 21-year-old man has been charged with murder. Indigenous affairs reporter Sarah Collard speaks to Cassius’s mother Mechelle Turvey about the powerful impact her son made on those around him – and the family’s pursuit of justice