But isn't that the point? If you don't declare the crime you're liable for tax evasion and can be prosecuted by the irs; if you do, you're going to be prosecute

But isn't that the point? If you don't declare the crime you're liable for tax evasion and can be prosecuted by the irs; if you do, you're going to be prosecuted by a different authority. And since nobody is going to self-incriminate, when they catch you you'll be prosecuted both for corruption and tax evasion.