Interviewing and Interrogation
Planning and structure
Effective interviewing begins with preparation: define objectives, review evidence, and decide sequence. Understand the difference between witness interviews, which gather information, and subject interviews, which test accounts against evidence. Know the value of free recall first, then structured questioning, then challenge with evidence.
Question types and memory
Candidates must recognize open questions, closed questions, leading questions, and multiple-part questions. Open questions elicit narrative and reduce contamination; leading questions suggest answers and undermine reliability. Understand that memory is reconstructive and vulnerable to suggestion, so interviewers should avoid feeding details and should record accounts as soon as practicable.
Rapport and ethics
Rapport-building is a legitimate technique; coercion, threats, promises of leniency, and deception about evidence can render statements unreliable or inadmissible depending on jurisdiction. Know the signs of compliance versus genuine admission, and the importance of documenting questions, answers, and context.
Traps in questions
Traps include assuming silence indicates guilt, treating a confession as conclusive, and believing that a confident witness is an accurate one. Another trap is failing to explore alternative explanations for an admission.
Rule of thumb
Use the "narrative first, evidence later" rule: let the subject give a full account before introducing evidence, so inconsistencies are genuine rather than prompted.
Worked example
A subject gives a vague account of a payment. The interviewer records it fully, then asks about specific dates and amounts, and only then presents the bank record. The contradiction is documented against a spontaneous account, strengthening reliability.