Wow thank you this is very interesting to know.
What happens if the suspect just continues to say ‘no comment’ the whole time? This is what he could possibly be doing right?
Or let’s suppose he’s confessed - they still don’t have to charge him so they continue to question him?
Without getting into the complexities of interview technique, I will endeavour to provide some explanation.
The interview needs to be planned around the 'points to prove', which are the individual required elements of offences in the criminal law. All the elements of an offence need to be proven for an offence to be 'made out' or complete.
It is important to identify where the evidence obtained fits into the points to prove and where there are gaps or the evidence needs to be more robust. This evidence is often obtained from eye-witnesses, expert witnesses, documents, forensics, CCTV, comms data, phone/computer interrogation etc. The guidance from the CPS prosecutor is an important factor.
Investigative interviewing explores the suspects account, the evidence, its context and the relevant 'points to prove'. Some points to prove can be challenging to show without skilled interviewing, e.g. The human conduct and the intent (Actus Reus and Mens Rea). It is also important to identify and explore the possible defences to the offences in question.
The suspect gives their own account of the events leading up to, during and after the suspected offences for which they have been arrested. The investigating officers will then drill down into the detail, methodically, also asking the suspect to account for the all the evidence (see 'special warnings' in PACE, which applies to evidence recovered in specific circumstances). Questioning will also seek to close down possible defences that an offender may seek to use, e.g. self-defence.
With a co-operative suspect, the basic objective is to facilitate them to provide their own account in detail and close down other possible explanations, that they could revert to in court.
With no comment interviews, the interviewers need to ask all the questions necessary to rule out justifiable explanations for the suspects actions, the evidence recovered and possible defences.
Section 34 of the Criminal Justice and Public Order Act (CJPOA) 1994 states:
Section 34 allows an inference to be drawn if a suspect is silent when questioned under caution prior to charge and subsequently relies upon a relevant fact at Court, which he or she could reasonably have been expected to mention when questioned. Just because a suspect declines to answer questions, does not automatically mean that an adverse inference can be drawn. It is only when he or she later seeks to put forward an account or explanation that the adverse inference provision is triggered.