The police watchdog has widened an inquiry into sex allegations against a senior Northland officer to include a leaked letter warning police bosses about the potential "scandal".
The Weekend Herald last week revealed the existence of an anonymous letter addressed to Police Commissioner Mike Bush and Superintendent Russell Le Prou, which mentioned the senior officer "having sex with a victim after being dispatched to a property".
Police did not investigate the sex allegation in the November letter, as it was just one paragraph in a five-page letter, which did not contain any corroborating details such as dates, or the name of the complainant.
"Police considered that this single paragraph (a vague comment via two anonymous sources) did not provide a basis upon which to launch an investigation. No further information was forthcoming which altered that view.
"Furthermore, police also had, and continue to have, doubts about the authenticity of the letter and whether it was in fact sent by any serving or past police member."
The police source who leaked it to the Weekend Herald had no doubt about the authenticity of the letter.
The police officer was not asked about the sex allegation, say police, and the letter was not forwarded to the Independent Police Conduct Authority.
Six months later, the woman made a formal complaint to the IPCA, which is now investigating. A separate criminal inquiry is also underway.
The officer has now been suspended and the complainant, who was the victim of a domestic violence case the officer investigated nearly 15 years ago, has been formally interviewed.
The police also did not forward the letter to the IPCA after the inquiry into the sex allegations was confirmed.
Asked whether police should have forwarded the letter, the IPCA general manager Warren Young last week: "I cannot answer that question without knowing exactly who received the letter and when.
"We are making further inquiries about it."
After police confirmed the letter was sent from Police National Headquarters to Le Prou in November, Young this week declined to comment.
"The letter will form part of our investigation and we cannot answer your question at this stage."
The Weekend Herald has chosen to not name the senior officer at the centre of the allegations at this time.
But he has been stood down pending the outcome of a criminal inquiry, an employment investigation, as well as the IPCA probe.
The Weekend Herald has obtained the woman's written statement to the IPCA, which said the alleged harassment began after the officer arrested her partner on domestic violence charges in 2002.
She received a few "kind and thoughtful" text messages but the complainant said the officer became a "bit too friendly"; buying her flowers, asking her out for dinner and giving her a nickname.
"He asked me out for dinner and wanted me to wear a red or black dress. I declined and felt a bit weird about it. He then arrived at the house with wine and pizza."
Even though the woman, who was in her mid-20s, began to feel "uncomfortable with the situation" she said she felt pressured to engage with him as he was dealing with the case against her partner.
In her IPCA complaint, the woman described several alleged sexual encounters.
"I was just frozen and silent. I had gone through two violent relationships and was still sorting out the mess of those.
"He was so much older than me, was meant to be helping me and I was relying on him.
"I was disgusted but a part of me felt like I couldn't say anything because he was the police and I needed his help at the time."
The criminal inquiry comes after several turbulent years in the Northland police district, including low morale, lack of staff, as well as the conviction of a senior detective for drug dealing.
Mike Blowers was a detective sergeant in charge of organised crime when he stole 34 grams of the Class-A drug from the exhibit locker at the Whangarei police station.
The Weekend Herald previously revealed how Northland police targeted a whistleblower before investigating the allegations against Blowers seriously.