What you have been doing is a good course of action as long as you can keep it up. Just keep quiet, but do not do anything unethical yourself. They will try to drag you into the gutter with them; don't let them.
Start keeping notes and documentation now. Every day after you leave work, write your notes. They may prove valuable in the future.
BUT - Do not remove copy, or email to yourself any proprietary information. They can fire you immediately for that.
If you do decide to report the misconduct to the company's hotline, be very careful. Even if you do it anonymously, your boss may be able to figure out who did it. Then be prepared for retaliation that may cost you your job. Your life may become hell as they pressure you to quit. Do not rely on the company promise of "we do not tolerate retaliation." I assure you from personal experience, that is not true.
If the misconduct is actually illegal, do not call the company hotline; call the appropriate regulatory authority. In that case, you may have some legal protection, but still be prepared, your life could become very unpleasant.
The best thing to do is keep quiet and get out if you can. Maybe you can transfer to another job or department.
I feel for you. You are in a difficult situation, but much respect to you for doing the right thing.