1.3 Evaluating questioning techniques
How many techniques did you come up with?
Below is a list of example techniques selected from crime dramas, along with information about whether the technique has been used in a real case and whether it is considered to be reliable based on evidence obtained from research.
| Technique | Used in a real case? | Is it reliable? |
| Polygraph (lie detector) | Yes | No |
| Threatening suspect physically | Yes | No |
| Physically harming the suspect | Yes | No |
| Pretending a photocopier is a lie detector | Yes | No |
| Sleep deprivation | Yes | No |
| Falsely claiming there is forensic evidence | Yes | No |
| Falsely claiming a witness has identified the suspect | Yes | No |
| Falsely claiming an informant has provided evidence | Yes | No |
| Offering a lesser charge in exchange for a confession | Yes | No |
You will have seen a clear pattern emerge: that a lot of techniques have been used to intimidate or trick suspects, but there is no evidence that they get reliable results. Research in this area suggests that although such techniques may increase the chances that the suspect will make a confession, they predominantly increase dramatically the chances that this confession will be false! This is one reason UK police do not ‘interrogate’ suspects, nor use false claims and other tricks, but instead interview them fairly.
DI Bullet did not employ any of the techniques from the list above in his interview, so does that mean the resulting confession must be true?