Criminal Investigations and Interrogation

서울흥신소 Interviewing a suspect or witness is often the starting point for a criminal investigation. Interviews contain some elements of persuasion, but the main goal is usually acquisition of information.


Police officers ask questions of people they have custody over or physically arrest. The questioning is considered interrogation. The Supreme Court has outlined specific requirements and procedures that must be followed by officers during interrogations.

What is Interrogation?

Interrogation is the questioning of persons detained by police, military personnel, or intelligence agencies with the goal of eliciting information, particularly information related to suspected crime. The interrogation process is largely outside the governance of law, except for rules governing the admissibility of confessions at trial and limitations on police powers to detain individuals against their will.

Interrogators have a variety of tactics and techniques that are designed to acquire the information they seek. Some of these techniques are predicated on generating internal psychological states of doubt, dependence, and self-conflict that weaken an individual’s resistance to disclosure. Others are based on exploiting a person’s natural emotions of anger, frustration, guilt, or anxiety to obtain incriminating information.

Regardless of the specific methods used in an interrogation, success depends on three components: competencies, concepts, and communication. Competencies refer to a person’s personal, professional, and social capabilities. Concepts represent knowledge of interrogation theory and implicit or explicit experience-based interrogation models. Communication refers to a person’s ability to manage social dynamics with citizens and apply goal-directed interrogation tactics and techniques.

The most successful interrogations are those that promote a suspect’s ability to testify in court (e.g., a “Mutt and Jeff” approach서울흥신소 ). Other factors influencing interrogation success include the interrogator’s logical or emotional approach, the case content, and the suspect’s personal background.

Types of Interrogations

There are several different interrogation techniques, ranging from psychological to physical. A police interrogator attempting to elicit truthful information may employ many persuasive elements, including making the suspect feel guilty or asking questions designed to expose deception. In the military, interrogators use techniques to cause emotional collapse in a captured captive and then seek confessions and names of targets, dates and places.

The interrogator begins by reviewing the source’s background and identifying any vulnerabilities that might make him susceptible to particular approach techniques. Then he prepares a plan of interrogation by selecting and modifying tentative approaches and deciding on the means for recording the results.

Once the interrogator has a full understanding of his source’s capabilities and limitations, he selects a basic topical sequence for interrogation and then refines it to include only those topics that are pertinent to his element’s collection mission. He also makes estimates about the type and extent of knowledge possessed by the source, and then adjusts his approach accordingly.

During the interview, the interrogator builds rapport with the source by discussing background details such as family, civilian life, friends, likes and dislikes. He tries to find common ground and shows a genuine interest in the subject. Then he can more easily ask nonpertinent questions, which open new avenues for the approach and allow him to assess whether or not the tentative techniques selected in the planning and preparation phase will work.


In interrogations, police use a variety of techniques to extract confessions from suspects. Some of these methods have sparked controversy because they can lead to false confessions from innocent people. For example, some police interrogation tactics, such as lack of sleep and persuasion, can cause suspects to collapse and change their perception of the situation so that they believe a confession is in their own self-interest. Other interrogation techniques include trickery and deception, and these can result in the suspect claiming guilt for crimes they did not commit.

A non-accusatory behavioral analysis (BAI) is a crucial first step in the interrogation process. This allows investigators to establish a rapport with a suspect and determine the suspect’s baseline behaviors. They then ask behavior-provoking questions to see if the suspect’s responses differ from their normal behavior. If the interrogator is convinced that a suspect is lying, they can move on to more aggressive and confrontational interrogation tactics.

Physicians should never participate directly in an interrogation and should only provide medical care to a detainee. This is to avoid contaminating the physician’s relationship with their patient and to maintain their neutrality and respect for the individual’s human dignity. However, a physician may monitor an interrogation to assess a detainee’s physical or mental condition. Physicians must disclose to the interrogator that they are assessing the detainee and that treatment cannot be conditional on the person participating in an interrogation.

Legal Issues

The ability to gather verbal statements from suspects and possible suspects can be critical for a successful criminal investigation. This information can be used at all stages of the legal process, including deciding guilt or innocence, determining competency to stand trial, and serving as testimony in court. Accurate information is essential, but interrogation techniques that increase suggestibility can cause suspects to provide inaccurate and misleading information.

Custodial questioning is a more involved process than non-custodial questioning. A person can only be subjected to custodial interrogation if they are a suspect or a person of interest in the case and is in police custody, which means they are either arrested or detained in such a way that a reasonable person would believe they are not free to leave. In addition, officers must read Miranda warnings to a suspect in custody before conducting any interrogation or other form of questioning.

Non-custodial interrogations do not require Miranda warnings. However, a person can only be subjected to non-custodial questioning if they are a suspect or if the officer believes there is sufficient evidence that they will incriminate themselves in the case. Non-custodial questioning is also conducted in a less formal setting than custodial interrogations and can involve more indirect methods of questioning, such as the Inbau Reid Buckley Method.

During a non-custodial interrogation, suspects must be provided with adequate accommodations and privacy. They should be seated comfortably and not have more than one investigator present in the room with them. The investigator should maintain a professional demeanor and not act overly aggressive or intimidating. Physicians may perform physical and mental health assessments of suspects, but they must never conduct or directly participate in interrogation. Doing so undermines trust in the physician as a healer and erodes the physician’s role as an impartial observer of the interrogation process.