Here is one for you.
You’re a fully sworn police officer with four months service. You discover that your younger brother (16) is stashing a fairly large quantity of cannabis in his bedroom. You come in from an early shift to find your brother smoking cannabis in an empty house. You know that you cannot just ignore it. What do you do?
This is the exact problem a close friend of mine is in and he really doesn’t know what to do (having worked so hard to get into the police in the first place).
prout de jure 
I will tell my brother to stop or I will be forced to report him.
If the rookie does not do that, his brother will not stop until he ruins or taints his career.
I’ve seen many cases like this.
I would definitely report him. I hate drugs.
There was an episode of The Thin Blue Line involving just this scenario. From what I remember, the PO told her sibling to get rid of it, only to discover that she was part of the crowd in a nightclub that was ‘busted’ for suspected drug dealing. She had drugs on her and the PO took them for her sibling after which the police dog ‘smelled her out’.
I guess the moral of the story was ‘don’t try to help your siblings’. It’s far better just to shop them in the first place. 🙂 And arguably more satisfying, too.