A police officer has been ordered to apologise to a prison guard for failing to investigate an alleged assault by a prisoner within the legal time frame.
Delays in the police probe meant that the Public Prosecution Service was unable to take a case against the inmate.
The prison officer told police in February 2016 that an abusive inmate had attempted to punch him and then spat in his face when he missed.
Police launched an investigation but did not submit a file on the incident, or apply for more time, before the case became statute barred after six months.
Following a complaint to the Police Ombudsman the PSNI watchdog found that the officer initially assigned to investigate the incident went on a period of planned sick leave four months after the alleged attack.
Before then he had sent an email to his supervisor outlining the cases he was involved in, and the actions needed to progress them in his absence.
The email incorrectly stated that the case would not become statute barred until a date in September, more than a month later than the actual date.
Police Ombudsman investigators also found that the officer failed to make appropriate CCTV inquiries, and did not make adequate efforts to interview the suspect.
It took him two months to obtain CCTV footage, and he waited a further two and a half months before submitting it to the relevant police department.
Inquiries also showed that despite being prompted by his supervisor to interview the suspect, the officer failed to do so.
When the officer appointed to follow up on the case went to complete the investigation, he found that the case was already statute barred, according to the Police Ombudsman's report.
The prison officer complained that not only did this mean there would be no prosecution, but the lapse in time also meant that the prison authorities could not investigate.
The officer was directed to apologise to the prison officer and a performance support plan was put in place by the PSNI.