Conversation is an essential part of everyday human communication. There are different kinds of conversations, which we need in different life circumstances. One type of conversation is interview or informative conversation that police officers use during the survey and investigation. That kind of conversation is different from a conversation over the polygraph tests, which is quite specific. Polygraph testing, and the specificity of its kind during the interview is the subject of this thesis. Subsequently empirical research was conducted by analyzing the contents. Polygraph techniques and polygraph in patients cause a kind of fear and discomfort. It is believed that the polygraph is reliable instrument that detects lies. Polygraph methods and techniques are trying to seek reliable indications of criminal offenses. There are certain conditions under which polygraph is applied. Not all criminal offenses or the subjects are suitable for a polygraph testing. Depending on the type of method used during the polygraph testing, depend polygraph results and its validity. Some methods are more reliable than others, which is supported by the literature. How depends on methods, so the results of polygraph testing depend on the experience of the examiner. To get the best results, the examiner should be trained and experienced practitioner. The respondents, in order to hide the truth,are using various techniques of lies, manipulation and deception. The behavior of the respondents is the biggest factor which reveals are they speak the truth or trying to deceive the examiner.