A very critical aspect of any investigation is the witness interview. Witnesses are a vital part of the discovery process, whether it is for a civil or criminal proceeding. How the witness is dealt with in the beginning of the investigation has ramifications that reverberate throughout the entire proceeding.Properly trained professional investigators benefit the legal practitioner enormously because they can approach witnesses as objective third-party contacts. While it is true that the investigator is working at the behest of the client, the professional investigator's mandate is to uncover and develop all of the facts in the case, not prove the client's theory of how things occurred.The most productive interviews are generally conducted in the witness' environment, at home most often, or if need be, at work. This produces a more relaxed state of mind and the witness is generally less defensive. It also allows the investigator to get a sense of the witness' background from items that are seen in the home or workspace.Developing rapport with the witness is vital to the process because frequently the investigator will be called upon to facilitate the witness' appearance at deposition and subsequently at trial. Rapport also allows the investigator to gently probe for bias or hidden agendas in the witness' characterization of events.