When people aren't under oath and/or don't face the possibility of jail for perjury, then nothing's stopping them from lying to save their hide.
Only a proper criminal investigation and possibly a proper court trial, with serious consequences for lying under oath, and a real judge and real jury will be any good.
After all, criminal behavior involving mistreatment of immigrants for personal gain, or, in other words, de-facto slavery, is a serious crime against humanity which must be dealt with by police and the judicial system, regardless of who the accused is, regardless of gender, ethnicity, political affiliation, etc.
No one can be exempt from investigation and a trial for criminal wrongdoing... no one, regardless of gender, ethnicity or political orientation/affiliation. Or wealth. The Charter of Rights and Freedoms does not excuse anyone at all for such things... not a single individual or group.