First hire an attorney who will learn the details and plan which agency is best to involve. Do not just call the St Charles police without a well crafted plan.
Act fast. You do not want to get caught up into something.
This would definitely be best handled with a one on one consultation with an attorney who can consider all the facts with you.
The law protects whistleblowers from losing their job. That being said, your job could still be at risk. Before you do anything, start looking for a new job and consult with an employment lawyer as to the best way to handle this.
Although AVVO describes this site as providing free legal advice, it is really a simple Q&A forum. The volunteer attorneys provide general answers. No specific legal advice is given here and no attorney-client relationship is established. For precise direction and legal advice, please consult in person with an attorney in your area. Be sure to bring all relevant paperwork with you.