The officer had been sent last year to arrest a suspect and search a house after the woman and her husband reported that they had received threatening and obscene phone calls and texts from an unknown number.

The man believed he recognised the caller’s voice and said the information provided would only have been known to one person.

The officer went to the suspect’s home but received no response. He then left a calling card with a request that he be contacted.

By doing so, the complainant alleged that the officer had alerted the suspect to police interest and given him an opportunity to dispose of evidence.

When interviewed by a Police Ombudsman investigator, the officer said he had received a “low key” request with no apparent urgency to contact the suspect. He believed he had been instructed to leave a calling card rather than to conduct an arrest and search.

However, an examination of police records showed that he had been tasked to arrest and search, but received no instruction to leave a calling card.

The supervising officer said the officer had been briefed about the background to the case, which involved intimidation including threats to damage property and endanger life and the improper use of telecommunication systems.

She expressed surprise that he had left a calling card given the nature of the task.

The Police Ombudsman investigator stated: “I recommended that the officer be disciplined for compromising the police investigation, for failing to act on an order, and for failing to keep appropriate notes in relation to the incident.”

The PSNI has since disciplined the officer.