If I understand your post correctly:
1. Someone or some agency is conducting an investigation.
2. You believe the investigation is unlawful.
3. You believe those conducting the investigation are bribing people.
4. You believe blackmail is involved.
5. You have been convinced by someone to do things that can later be used against you.
Is that correct?
I recommend you meet with a WA state criminal defense attorney (in particular if you are the subject of the investigation) and dicsuss what you have uncovered. That attorney MAY be able to advise you on what steps to take after he/she hears your evidence, somthing more than the accusations you posted here.
READ THIS BEFORE CALLING OR EMAILING ME: I am licensed to practice before the state and federal courts in Virginia. We have not established an attorney-client relationship unless we have a signed representation agreement and you have paid me. I am providing educational instruction only--not legal advice. You should speak with an attorney to whom you have provided all the facts, before you take steps that may impact your legal rights. I am not obligated to answer subsequent emails or phone calls unless you have hired me. I wish you the best of luck with your situation.
What? I don't understand. You are saying that an investigation is happening and PIs are bribing people for help or to fabricate evidence.
If you are afraid of being manipulated by police in an investigation, you should make sure that you retain an attorney who will notify the police that you are represented. That will stop the police from trying to contact you.