A 16-year-old boy charged with his mum's murder has denied killing her during an appearance in the Perth Children's Court. The boy is accused of killing his mother and attempting to kill his sister at their Bentley home, in Perth's southeast, on Tuesday. Picture: Main Roads WAAfter two charges were read to the boy, the matter was moved to another court where it was heard by Judge Wendy Hughes. Picture: Main Roads WAThe grim discovery shut down a busy stretch of Albany Highway during Perth's morning peak. Picture: Main Roads WASeemingly wearing a dressing gown, the young girl ran 600m down Albany Highway into the neighbouring suburb of Cannington, where she called triple-0.