Formulate your questions so that they did not have any reproaches. Then the answer will be more open, you will be better able to clarify the situation and to understand the unconscious attitude of the person – will alarm it, or remain calm.
To find out is your interlocutor is of particular interest in a certain topic or a specific person, do the following: give him a variety of information touching on a specific topic. During the conversation he either will be curious only to one subject, or Vice versa – equally talking about all show his indifference.
The basis is a specific fact that you known. Ask the personwhom you suspect about it. If he wants to hide something, you would know.
Put next to two people. One of them must be the person you want to find out information. Let them know that you don't trust both of them. Then be sure to tell that one of them is very dangerous for some reasons. Watch - someone will start to worry.
Ask a direct question: "How would he have done in this situation?" Be sure the source will tell. A psychological trick is that if the resolution of the situation involves only one reasonable solution, and your partner in conversation will give some ridiculous answer, then you need to look at him.
You are going to learn about the secret hidden behind seven seals, but not to behave like Sherlock Holmes. You, first and foremost, not a detective, and a subtle psychologist, who must establish contact with the interlocutor. Behave naturally and friendly.
If the person covers his mouth with his hand, according to the sign language, that means he's hiding something and doesn't want to Express their position.
A number of people prefer a scheme of "wolf — prey". If you know that the other person is vulnerable, vulnerable to influence and really has something to hide, act aggressively, ask sharp questions, you attack. You will see that it will start to stumble, stutter and make excuses that do not would have absolutely, because you have no direct evidence. However, keep in mind that perhaps your companion is a wolf in sheep's clothing, and the grin you will have together. And then it will rudely ask why you sticking your nose in his business.