Abstract: This article explores problems with interrogation and interview of witnesses during the investigation stage and their legal outcomes. It is about the witness and his importance as an evidence. In particular, with the obtaining of information from the witness and the procedures that must be followed so that the information is obtained in the interview is admissible at the main trial in both cases wether the witness appears or not. Problems arise when the witness does not appear at the trail, because criminal procedures are based on the principle of directness, which means that all evidence has to be proven by due process. Besides this, there is a problem with the right of the defendant to confront the accuser. This article analyzes all these problems and dangers to due process and illustrates possible solutions.