The standard of proof for allegations of criminal behaviour is "beyond reasonable doubt".
Interviews concerning criminal allegations will be recorded. The relevant guidance for such interviews is contained in the Police and Criminal Evidence (Northern Ireland) Order 1989 (Article 60 and 65) Codes of Practice Code E.
Such interviews will also be carried out under caution. If you are not under arrest the interviewer will advise you are free to leave should you wish, and also that if you stay for interview you are entitled to free legal advice.
In a criminal interview, while you are not entitled as of right to have a 'friend' or Federation Representative present, the Police Ombudsman Investigation Officer may permit a 'friend' or Federation Representative to be present.
The law requires that at the end of an investigation of alleged criminal behaviour, the Police Ombudsman must submit a file to the Public Prosecution Service (except, for example, in cases where CCTV evidence clearly shows that the officer is not culpable). This file will include a recommendation as to whether, based on the evidence of the case, the Police Ombudsman believes the officer should be prosecuted.
The final decision, however, rests with the Director of Public Prosecutions. The Public Prosecution Service (PPS) will evaluate the evidence within the file and determine whether there is 'a realistic prospect of conviction', i.e. that the evidence supports the allegation beyond all reasonable doubt, and the prosecution is in the public interest.
If the PPS is satisfied that this standard has been achieved they can direct that you be charged with the offence(s) and appear before a court.