[froo]

Extradition when there are no charges is unusual.

Unusual yes, but not unheard of.

As a personal anecdote, there is a close friend of my family who has been facing extradition to another country merely for questioning over something that he allegedly did in 1944.

http://en.wikipedia.org/wiki/Charles_Zentai

[keithpeter]

"The Hungarian authorities have not explained why they could not question him in Australia under the treaty on criminal cooperation."

Seems very similar.