My Boss is committing tax fraud and money laundering, and does not pay my taxes?

I handle their finances and accounts. They have only 2 people (his wife and himself) accounted for as employees and only those taxes are taken care of. The other 12-15 people are not, including myself. He previously told me in confidence that he kept a stack of his paychecks untouched so that it wouldn't appear that he made too much money by the end of the fiscal year; afterward he cashes them. I confronted him with the information when I realized my rights (I am opening my own business and have gone through all the paperwork and learned of an employer's responsibilities), and I got kicked out. I get a weekly paycheck to not go in, but there is a constant threat. He hasn't fired me because I told him about my rights as an employee, and we both know that he can't do that. Until now. Now my biggest problem is that I am no longer receiving a check and I've tried to contact both the Payroll company and the IRS. It is not right that so many people get taken advantage of by someone who does not pay any taxes. I am deeply in debt because of taxes. But no one out there will listen to me. Who do I contact to report him?