Would be better if your friend is lawyer and take $1/yr(or higher) for the service so that attorney-client privilege can be applied.
edit: ah, future crime cannot be protected.
edit: ah, future crime cannot be protected.
Lawyers have a duty of care to the court and they will absolutely drop your ass if you try to make them keep quiet about your crimes.
(This is not to be confused with them representing you in defense. You can tell them about your crimes if the government is trying to get you for said crimes.)