Former Senior Military Interrogator Matthew Alexander (in a 2010 interview) defined the most important interrogation techniques an interrogator needs. Stating that torture is not effective and is actually counterproductive, Alexander stated the three best traits of effective interrogation are training and education on the cultures and practices of future prisoners, better accommodations for prisoners, and alternative cross-examination techniques. Alexander, in the interview, noted that Indonesia treats the prisoner as an individual, and this seems to help with extracting information.
Chapter four of Criminal Investigation lists the important characteristics of the interrogator. First, the interrogator must possess knowledge about "the art and science" of interrogation. Second, the interrogator must be both persuasive and possess perseverance. in this, he or she must be a master of voice (inflection, pace, and tone). Lastly, the interrogator must keep an open mind about the prisoner.