text: FM 2-22.3
  Chapter 9
  Questioning
  9-1. Questioning is one of the five phases of HUMINT collection. Developing
  and using good questioning techniques enable the HUMINT collector to
  obtain accurate and pertinent information and to extract the maximum
  amount of information in the minimum amount of time. The HUMINT
  collector must know when to use different types of questions.
  GENERAL QUESTIONING PRINCIPLES
  9-2. Questions should be presented in a logical sequence to avoid neglecting
  significant topics. The HUMINT collector begins the questioning phase with
  the first topic in the sequence he tentatively established as part of his
  questioning plan. He obtains all of the source's pertinent knowledge in this
  topical area before moving on to the next topic in his sequence. The only
  exception is exploiting a hot lead, which is discussed in paragraph 9-21.
  9-3. The HUMINT collector must at all times remember that his mission is
  the rapid collection and dissemination of accurate information. He must not
  allow himself to be sidetracked into nonpertinent discussions or debates nor
  should he express distaste or value judgments on the information being
  supplied unless that is a planned part of his approach technique. The
  HUMINT collector uses vocabulary that is clear, unambiguous, and
  understandable by the source. The source may not be on the same
  intellectual level or have the same degree of education as the HUMINT
  collector, so the HUMINT collector must adapt his questioning to the level of
  the source. The source may also have specific technical knowledge, more
  education and/or a higher intellectual level than the HUMINT collector. In
  this case, the HUMINT collector normally relies on prepared questions or
  technical support for his questioning. Without good systematic questioning
  techniques, even the most cooperative source may provide only minimal
  usable information.
  DIRECT QUESTIONS
  9-4. Direct questions are basic questions normally beginning with an
  interrogative (who, what, where, when, how, or why) and requiring a
  narrative answer. They are brief, precise, and simply worded to avoid
  confusion. The HUMINT collector must consider the probable response of the
  source to a particular question or line of questioning and should not, if at all
  possible, ask direct questions likely to evoke a refusal to answer or to
  antagonize the source.