information developed. The human factors that affect the powers of perception and
memory may be the cause of the differences; they should be considered but should
not be relied upon too much to explain differences or conflicts in different
accounts of the same event. Sometimes, the cause of the differences may be found
only in the motivation or prejudices of the interviewee who lied when he told his
account of the incident.
(3) Review the entire case as it has been developing and give particular
attention to the remaining gaps in your knowledge of the case.
Try to get a
clearer picture of the case than was possible before the interview.
c. Performance of the Interviewer. The MPI who truly wants to improve his
ability to interview persons successfully, evaluates himself during and after each
He evaluates both his approach and his manner.
This procedure is
particularly necessary when he has been unsuccessful in getting from the
interviewee all the information that he was believed to have.
PART K - INTERROGATION.
a. An interrogation is the questioning of a person suspected of having committed
an offense; it could be the questioning of a person who is reluctant to make a full
disclosure of information of value to an investigation.
Interrogation serves to
answer the basic questions of an investigation, the who?, what?, where?, when?,
why? and how?
b. The purposes of an interrogation are to:
(1) Determine the facts of a crime.
(2) Develop information that will help you to secure independent testimony and
physical evidence to prove the truth of an admission or a confession.
(3) Extract truthful information from a lying, evasive, or reluctant witness,
false accuser, or other uncooperative person. Any of these may withhold valuable
information which could lead to the solution of a crime.
(4) Learn the identity of an accomplice to a crime and/or the details of any
criminal plan or scheme.
(5) Get a confession or admission to the crime under investigation.
(6) Develop the details of any other crime in which the suspect may have been
(7) Recover the fruits of a crime.
2. WHOM TO INTERROGATE.