My friend is stealing should I tell?

You may have heard the expression"you have a tiger by the tail", in a way you have, you need to get away from this gang before you end up in serious trouble with a record of convictions which will haunt you for the rest of your life making it difficult if not impossible to become a trusted member of society, how you can manage it is up to you, I understand that among your acquaintences there will be some who will not take lightly to you wishing to break away from them, and may even try to prevent you from doing it, at least I feel this could be so, it is yourself you should worry about getting into trouble, not her if you are in her company when she gets caught it would be a safe bet that you will come out of it worse than her unfairly the blame will be made to be yours I'm sure.