Protecting emails of an identity theft's criminal, someone who has stolen emails accounts, that is almost laughable, almost.
If this is the Gov. not gov. (as in local) they already have access. Maybe it's just about using the info legally in court.
The feds were also asking for access to full 1 & 1 Media accounts. This statement means federal not local government.
The chances are that investigators already have data from the NSA. This is just to get evidence that they can use in court. Parallel construction.