Can I get wages back?

At my current public company, I am being investigated by HR for falsifying expense reports. They believe there were some personal expenses that I charged to the company, which I admitted were a mistake and would pay the company back. My work email was disconnected on Friday, so I believe they are firing me this coming week. Over the last 3 years, I have seen many employees break rules and their managers covering up for them. I know for a fact there are employees that have falsified their licenses and qualifications in order to run our ops and mgmt plants. This is a fireble offense. I know that there are other employees t have used their business cards for personal reasons as well. I would like to know if there is a case for me to sue the employer and get some of the wages back from what could have been a long-term career at this company.