I was watching this ( film i think it was ) where the government ( secret service , whatever ) wanted this 'problem' taken care of .
The people that were supoosed to the deed were instructed that if they got caught the government would deny any knowlege or that they had sanctioned any such acts .
I'm sure in the real world that no government would admit that there is a 'department' which carries out dirty deeds .
However in the real word i beleive it would be safe to say that such a kind of department does exists .
Assuming that it does , who in their right mind would voluntary work for such a ' department ' ?
Such tasks might be 'contracted out'. The French secret service hired criminals to assassinate Basque suspects.
Then there are people who might think themselves to be James Bond types who'd be willing to do whatever they were asked to do.
Read some of Andy McNab's books and also those by Stephen Leather. Quite eye openers. Andy McNab is ex-SAS and his is writing is excellent and very graphic.