Police interrogation is the process of questioning with the key objective of obtaining particular information during an investigation. Police, military and intelligence agencies are the most common interrogators; with suspects, victims and witnesses to a crime the usual subjects of the interrogation process.
Police officers are highly trained in the use of psychological tactics after undergoing a course of instruction in using interrogation techniques during their basic training. Officers also learn about detailed interrogation in their further training. Advance police training courses provide the knowledge officers will need for to embark on a criminal investigation, fraud investigation or child protection inquiry.
In 1937, the Supreme Court of the United States ruled that confessions obtained by force could not be used as evidence at trial. American scholars consider that the success in police investigation is between 42 percent and 55 percent, as this is the percentage of suspects who confess to a crime. Meanwhile, British legislation outlining interrogation procedures and details can be found in the Human Rights Act 1998; Regulation of Investigatory Powers Act 2000; Anti-terrorism, Crime and Security Act 2001, and the Terrorism Act 2006.
There are some countries in which concerns have been voiced by human rights organizations, over the suspected use of physical interrogation techniques. These include police officers depriving the suspect of food and water; of making them suffer physical discomfort and the use of bright lights and water as they face questioning. Other methods include long-term isolation, and beating with rubber hoses, which do not leave visible marks on the suspect.
Police investigators are trained in using psychological approaches that may take advantage of certain weaknesses in human nature in order to get a confession. Sometimes police officers leave behind coercive forms of interrogation and concentrate on legal and more useful techniques. The ‘Good cop, bad cop' method is one of the simplest and most effective in police interrogation. It involves a detective who ‘browbeats' the suspects and another who acts as if they are looking out for them. This uses the psychological presumption that people are keen to trust someone they see as a protector
Another technique of interrogation is called maximization, where a police officer tries to scare the suspects by telling them all the bad things they will face if the court convicts them. This method uses the presumption that fear will make people talk. Polygraphs are another police approach in interrogations but this method is not always admissible in court and the other disadvantage of this technique is the expense.
The technique of psychological manipulation starts with the interrogation room, which is specially designed to create a sense of powerlessness and discomfort. The furniture of the room, which consists of a desk and three chairs and bare walls, strengthens a sense of exposure, isolation and unfamiliarity. Before the interrogation starts, police officers will try to determine innocence or guilt. Misleading tactics in interrogation are allowed in most of cases. For example, a police officer may tell the suspect their fingerprints were found at the crime scene, even if they know they were wearing gloves.
John Reid's ‘nine steps' guidelines provide useful techniques for an interrogation. This includes:
- Confrontation - the phase at which the interrogator gives the facts of the case and informs the suspects of the evidence against them;
- The theme development phase – when the detective makes a story saying why the suspects committed the crime;
- The shopping denials phase – when police officer is aware the suspect may make a denial and tries to stop them. This step acts to keep the suspect's confidence at a low;
- The overcoming objections step - helps the investigator to make every objection of the suspects to end up looking more like an admission of guilt;
- Getting the suspects' attention - when the suspects are already frustrated and unsure. The police office, in turn, tries to take advantage of that insecurity by pretending to be the suspects' comrade or ally;
- The suspect loses resolve - when the body language of the suspect indicates surrender and the interrogator takes the opportunity to lead them into a confession;
- Contrasting alternatives – the next step is when the police officer offers two motives for the crime – one is socially acceptable and the other is morally unacceptable;
- The alternative - when the suspects choose an alternative, the confession has started.
- The last step of the interrogation is the confession itself.