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.
Witness Interview versus Interrogation
First, what is a witness interview and what should a successful witness interview accomplish? Recent world events, as well as television shows and movies featuring cops, FBI and counter-terrorism agents, may have confused people about the difference between an "interview" and an "interrogation".
The United States Air Force actually defines the two words this way:
Interviews are cooperative, informal meetings where the interviewer approaches the witness as an equal and encourages their cooperation, allowing him or her to relate observations without interruption or intimidation.
By contrast, "interrogation" implies questioning on a formal or authoritative level, such as a lawyer-to-witness situation, a police officer-to-suspect session, or a parent-to-child encounter.
At FPI, we define an interview as a dialogue between two people - the investigator and the witness - in which the investigator's task is to facilitate an accurate recollection of events, of conversations or of any other facts that will help establish the truth about that which is being inquired into. An interrogation, on the other hand, is primarily about confronting a witness in order to get information the interrogator believes the witness or suspect has. An interrogation may occur at some point after an interview and may focus on contradictions and suspected lies in the witness' statement.
The goal of a witness interview is to discover if the individual being interviewed has significant knowledge relating to the case at hand - information that will help establish facts or information that either corroborates or refutes other versions of the incident - and to elicit as much of that relevant material or useful information as possible. During the witness interview, the investigator seeks to discover what the witness - through all five of their senses: sight, hearing, smell, taste and touch - has observed. If the witness does, in fact, have important information to provide, the secondary goal of the interview is to obtain a signed witness statement.