- When planning who to interview, work from the center of the issue outward. Identify the people who are likely to provide the best information. When conducting the interviews, start with witnesses that will provide all relevant background information and frame the issues. This will allow the interviews of key witnesses to be as complete as possible, avoiding the "backtracking" described above.
- Concentrate on those witnesses who would have the most direct knowledge about the events in question. Without unnecessarily disclosing the evidence obtained, attempt to seek information that would support or refute information already obtained from others. In closing an interview, it is appropriate to ask if the witness knows of any other persons who might have useful information or any other information the witness believes may be relevant to the inquiry.
- Any information that is relevant should be collected regardless of the source; however, investigating officers should collect the best information available from most direct source.
- It may be necessary or advisable to interview experts having specialized understanding of the subject matter of the investigation.
- At some point, there will be no more witnesses available with relevant and useful information. It is not necessary to interview every member of a unit, for example, if only a few people have information relevant to the inquiry. Also, all relevant witnesses do not need to be interviewed if the facts are clearly established and not in dispute. However, the investigating officer must be careful not prematurely terminate an investigation because a few witnesses give consistent testimony.
6. Conducting witness interviews. Before conducting witness interviews, investigating officers may consult Inspector General officials or law enforcement personnel such as Military Police officers or Criminal investigation Division agents for guidance on interview techniques. The following suggestions may be helpful:
- Prepare for the interview. While there is no need to develop scripts for the witness interviews, investigating officers may wish to review the information required and prepare a list of questions or key issues to be covered. This will prevent the investigating officer from missing issues and will maximize the use of the officer’s and witness’ time. Generally, it is helpful to begin with open-ended questions such as "Can you tell me what happened?" After a general outline of events is developed, follow up with narrow, probing questions, such as "Did you see SGT X leave the bar before or after SGT Y?" Weaknesses or inconsistencies testimony can generally be better explored once the general sequence of events has been provided.
- Ensure the witness’s privacy. Investigating officers should conduct the interview
