Michael Cohen will give Congress evidence of Trump criminal conduct since becoming president

During his much-anticipated public testimony before Congress, President Donald Trump's former longtime attorney Michael Cohen will provide evidence of his old boss' criminal conduct since becoming president, a knowledgeable source about what to expect told NBC News.

And, as this source laid out, there is much more congressional investigators and viewers can expect Cohen to provide.

Trump's ex-attorney will detail what he will describe as the president's lies, racism and cheating as a private businessman while Cohen spent a decade working for him, the source said.

Cohen will also reveal information about Trump's financial statements and may actually provide the statements, the source said. This information would require the president's long-held secret tax returns in order to verify, providing an avenue for House Committee on Oversight and Government Reform to request those returns. As the source said, Trump deflated the value of his properties in some cases so to reduce his property tax.

Related: Trump’s former lawyer, Michael Cohen pleads guilty

The source said Cohen will address his motives for lying on behalf of Trump and why he lied to Congress about the Trump Tower Moscow negotiations — a charge he pleaded guilty to late last year. Cohen will additionally discuss if anyone told him to lie.

In addition to his public session on Wednesday, Cohen will testify behind closed doors to the Senate Intelligence Committee on Tuesday and the House Intelligence Committee on Thursday.

The House Oversight Committee earlier provided the framework for what they want Cohen to address during his open testimony.

In December, Cohen was sentenced to three years in prison for what a Manhattan federal court judge called a "veritable smorgasbord" of criminal conduct, including facilitating secret payments to women who claimed they had affairs with Trump, lying to Congress about the president's business dealings with Russia and failing to report millions of dollars in income.