Okay, I just found out that if you commit a crime and are still one of the suspected culprits, you must remember these things: Detectives or Interrogators decipher your movements as ‘Anxiety.’ If you show excess movements, they will perceive it as nervousness and showing calmness or few body movements indicates unsurety.
As for the verbal communication to make you speak, it's best if you will give an answer, make preparation as sticking to one role. Be vague if you want to be vague and be specific if you want to be specific. However, those are not really applicable to certain crimes: Being vague doesn't mean a leeway to some uncertain things ‘because of the capability of our memories’ and being specific doesn't mean a bigger yet narrow picture of the incident to cover the crime. For me, be the interrogator. Learn and study words where you can put people who question you an implicit boundary or reversing the role from being pried to the one who closes the lid without them knowing.
If the interrogator is a psychologist, give them more or less movements that make you be the ‘opposite of real you.’ Not all judgements are right, if there's a plan A then there's a plan B. So, there's Hypothesis 1 and there's Hypothesis 2 up until the end where they will feel that they ‘seem’ to see through you. Just be mindful that not all psychologists are assumptionist, they tend to speak words where you will be comfortable to say ‘Yes’ to their questions like “....Does it seem that way to you?” where you will speak openly because they hypothetically guess it correctly…
Why am I sharing this bad information? Don't do crimes please.