Trust me, a little violence helps. Like interrogation, can't touch, beat, slap, shout etc, sure no results. If violence is moderated, chance of success up at least 50%.
Your call.
You must be joking like...
IO GD : Hello, good evening, I'd like to ask you some questions.
Accused : Ask your head, everything I don't know.
IO Ram : (Smack punched on his head)...now you know something or not?
Accused : Wah sir, don't like that lah, I can complain, you know?
IO Ram : (Smacked another punch on the stomach)...complain what, huh?
Accused : Wah sir, don't like that lah, nothing lah, just joking.
IO Ram : Now, you tell IO GD what really happened, otherwise I'm going to use my legs...on you.
Accused : Yes sir, yes sir...this was what really happened... ...