Income is income. The IRS doesn’t really care where it comes from, as long as y they get their share. If you report it as “off-shore sex work” or “donations for digital paintings” or some such, they don’t care. Their job is to collect taxes.

The IRS is looking for evidence that you’ve paid what they think they’re old, or have documentation to justify the discrepancy. They are not an agency equipped to chase down criminals that pay their taxes.