So they have to be interviewed, but are the compelled to give a statement or are they free to remain silent as is everyone's rights under miranda?
The supreme court has ruled that a compelled statement is immunized, in that the officer is giving that statement and is immune from prosecution based on information in that statement.
Velma: They're compelled to give a statement in the course of an administrative investigation. That statement is kept wholly walled off from the criminal investigation, for which no statement is compelled. In Rod Underhill's opinion, that's still enough to warrant blanket immunity under Oregon law. But plenty of state's do it like this.
The supreme court has ruled that a compelled statement is immunized, in that the officer is giving that statement and is immune from prosecution based on information in that statement.
See Garrity VS New Jersey.
http://www.garrityrights.org/basics.html