I don't think FIFA's bylaws can somehow supersede those of every country on earth. This is a criminal investigation into FIFA by the US, not a FIFA investigation into a FIFA official by another FIFA official.

I know that the TPP is happening and it's being done without much oversight. But I suspect that if FIFA had somehow attained worldwide diplomatic immunity for its officials we'd know about it. And once an official stepped down, well, they'd then lose that immunity (not that it's ever existed) and would again be open to prosecution.

> I thought by FIFA's bylaws once a person leaves their position, all investigations into any ethics issues cease? Or is that just internal investigations?

Its just internal FIFA investigations. If a private organizations by-laws could cut-off criminal investigations, every criminal would be creating their own organizations with by-laws structured in a convenient way to do that.

Why would FIFA's bylaws have anything to do with a criminal investigation?

Obviously that's just internal investigations. The DOJ doesn't care about your employment status.