It would be quite an interesting career path i must say, also somthing like the Fire service (was going to apply in my own country). But being realistic i would imagine they would really only hire Japanese people for this type of work. It would require an extremely high level of Japanese and also quite deep knowledge of the structure of the their law system, sociology, psychology etc and also possibly long enough training periods like in most countries. Also note some countries require citizenship before you can apply for such work.