john and mark are two siblings who live together. john is 20-years-old and mark is 12-years-old. Ann and jack are two of their neighbours.

One day, a friend of john's brings a couple of small boxes containing small plastic sachets with white powder and asks john to hide them somewhere safe until she comes to collect them. john accepts the request but finds the secrecy odd. He opens one of the sachets and realises that these are drugs. Concerned, he hides them in the cellar.

Ann suspects something 'fishy' and knowing that john has had problems with the police before, threatens him that if he does not steal jack's $500 bike, she will tell the police that he is involved in illegal activities. As john says nothing, she adds that she will also run mark over with her car when mark returns from school, and make it look like an accident.

john is terrified of the threats. john also remembers that he once took jack out and paid $100 for his drinks, but jack never reciprocated. john takes jack's bike (which was chained to a tree on the kerbside outside jack's property) and moves it less than a metre away, across the fence, onto Ann's property.

jack confronts john about the stealing of the bike. mark observes the heated discussion between john and jack. mark takes a stick from the ground and hits jack, causing several bruises on his leg.

Annoyed, jack goes to the police and complains that john and mark are involved in unlawful activities. Upon a lawful search of john and mark's residence, the police discover a quantity of 50 grams of white powder. Lab tests conclude that the white powder was amphetamine.

With reference to relevant authorities, consider the following:

A.1. john's liability in relation to the taking of jack's bike and any relevant defence/s.

A.2. john's liability for drug-related offences.

A.3. mark's likely charge for the injuries caused to jack, and mark's liability in the light of his age. NB: In relation to the charge, you should not analyse in detail the elements of the offence committed by mark. Simply indicate what the charge is likely to be, explain why, and provide the relevant authority.]

• Cases and legislation: (Royall v R (1991)) or (s.18 Crimes Act 1900(NSW))