Witness testimony is the one of evidentary actions in criminal proceedings by which we obtain one of the most important evidence. The witness is a person who is different from the defendant and who, with his testimony, provides the necessary information on the criminal offense, his perpetrator and other important circumstances of the criminal offense. There are different types of witnesses depending on how they give their testimony in criminal proceedings. The examination of witnesses is carried out through several phases in which the identity of the person being examined is to be established, invited to present everything he knows about the criminal offense and to examine it in order to get a complete insight into whether the witness is lying or telling the truth. Since this is a very important piece of evidence, it is necessary to conduct the examination of the witness as much as possible in order to obtain as much information as possible on the criminal offense the witness is witnessing. Success in carrying out this demonstration is largely dependent on the examiner's ability to create a suitable environment in which the person who witnesses will not feel endangered. It is also necessary for the examiner to assess whether witnesses are truthful or lying, according to the gestures of witnesses. Testing a witness is a complex process of finding facts about a criminal offense whose performance depends on a number of factors.