Meatball and FlyVMO,
I haven't heard of their being arrested. Yet. The AirForce say officially and quite prudently there are no grounds for laying blame yet, although individuals therein and connected thereto have given the press their personal opinions which weigh pretty heavily against the Legacy crew.
I won't begin to try to explain the legal system in Brazil other than to say that an accident of this magnitude allows magistrates in a broad range of jurisdictions to issue court orders based on incomplete information.
That doesn't mean the two Legacy guys will be put behind bars. They'll have to wait out the investigation period and probably a good part of the ensuing legal battle in a hotel. Given the widely published "evidence" (yes, that too could be baloney) that they took some liberties prior to the collision, they'll be the targets of considerable public hostility for some time.