PSNI failings compromised an investigation into off-duty police officers involved in a fight with members of the public, the Police Ombudsman has found.
Three off-duty officers involved in the fight in Coleraine on April 11, 2015 and another, who provided a statement about what happened, were not properly challenged about inconsistencies in their accounts, Dr Michael Maguire found.
A delay in submitting a file to the Public Prosecution Service (PPS) also meant the officers could not be considered for prosecution. The PPS asked the Police Ombudsman to independently investigate the police handling of the incident.
The fight began in the toilets of a pub and continued in an alleyway. Police arrived after 999 calls were made by the officers.
Four members of the public were arrested at the scene and another two in subsequent weeks. They were later charged with public order offences and a file was submitted to the PPS.
The off-duty police officers were initially treated as witnesses but were interviewed as potential suspects after counter-allegations were made.
Police Ombudsman investigators found the investigating officer failed to make full use of CCTV and mobile phone footage to challenge inconsistencies in their accounts. He was also a month late in submitting a file to the PPS, which meant the officers could not be prosecuted.
The officer blamed the case's complexity and denied showing favouritism towards the officers.
One officer involved in the fight was also asked why he had accessed police computer records about the incident without authorisation. He claimed he was checking times for his statement.
Dr Maguire recommended the PSNI discipline the officer and also recommended disciplinary action against the investigating officer for failings which compromised the fairness and impartiality of his enquiries. The PSNI implemented both requests.
Dr Maguire's recommendation that the four off-duty officers should be disciplined over inconsistencies in their accounts of the fight was not implemented.
However, the police did discipline the four officers for inappropriate off-duty conduct.
Chief Inspector Mark McClarence said: "PSNI accepted the findings of the Ombudsman in this case and implemented an internal disciplinary process which resulted in the officers receiving a misconduct outcome."