It was the year of the brutal murder of a Saudi journalist, the eruption of Kilauea in Hawaii and the election of Brett Kavanaugh to the Supreme Court in the US. This summer we look back at the big stories of last year around the world and closer to home. This story was first published in November.
An investigation has been launched by military police after a complaint by a woman who was cheated on by two intelligence specialists.
Alexandra Kitto, 32, told the Herald on Sunday she complained to the NZ Defence Force because she believed her former partners' specialist training cultivated deceit and secrecy which had spilled over into her life.
The Upper Hutt woman believed there were problems with the culture and environment in NZDF's intelligence workforce which needed addressing.
The failed relationships, with men the Herald on Sunday has chosen not to name, included one in which the father of her child would claim to be disappearing on secret business in the service of New Zealand but was actually spending weeks at a time with another woman and her children.
The other man used postings to Australia to secretly maintain a relationship with another woman, Kitto said.
She knew they worked in military intelligence and that they couldn't talk about what they did and where they did it. But she didn't expect service to New Zealand would be used as camouflage to carry out secret lives.
NZDF will not answer any questions about its training of intelligence officers, the current military police investigation or national security.
"There are privacy issues involved, and NZDF has no comment to make."
NZDF would also not confirm an investigation by military police, despite the Herald on Sunday obtaining evidence which shows senior investigators have asked questions about security concerns around the relationships.
Academic research has raised issues around difficulty experienced by undercover police officers in separating work personas and skills from behaviour expected in domestic situations.
The first of Kitto's relationships lasted from 2012 through to 2015. She met the man when he came into a shop she was working at in Upper Hutt.
He was working at the nearby Trentham Military Camp but was in the process of being transferred to Christchurch's Burnham Military Camp.
"All I knew was that he was in the intelligence corps. Even today, I don't know what he does."
The Herald on Sunday has confirmed the man - who was previously in uniformed service - works as a civilian employee in signals intelligence in a top-secret section of the NZ Defence Force.
Their son was born in 2013. On New Year's Eve that year, she overheard the man listening to a phone message and had her suspicions aroused through the sound and tone of a woman's voice.
When the phone next rang, Kitto answered it and heard the same woman's voice, but the call was disconnected.
Confronting the man, it emerged he had been continuing a relationship with a woman in Christchurch who had two children.
"It was the worst day of my life. My world just shattered."
They continued their relationship for another year as Kitto tried to work things out with the man.
Over the year Kitto said she figured out the man had used his classified work and the secrecy around it as cover for the double life.
She said one example was a phone call from the man when she was eight months' pregnant, during which he told her: "I have to go away for work. I can't tell you how long I'm going to be away for or where I'm going but I'll be back in time for the birth."
It was revealed he had actually been with the other woman and her children at their home.
The other woman, who did not want to be identified, confirmed the overlap to the Herald on Sunday. She said she did not believe the issue was one for NZDF but Kitto and "a broken heart".
"They are nice guys, infidelity aside. I was disappointed. I can handle anything without being lied to. It was unfortunate but we've got through it and we're still mates," she said.
Kitto still sees the man regularly because of the couple's son. She described him as a good father.
This year, Kitto met another serviceman - also based at Trentham - via Tinder.
The relationship ended after about seven months when she discovered he already had a long-term partner.
In this case, the man works in protective security and during his time with Kitto shared details of interrogation and surveillance training he was undertaking.
Kitto said she had reservations about becoming involved with another man in uniform, particularly after finding he worked in intelligence-related areas.
Yet reassurances and a clear understanding they were in an exclusive relationship provided enough comfort to give it a chance, she said. "They are masters of deflection."
But the man visited Australia, where the other woman lived, for periods of time during which he continued their relationship.
The deception collapsed after Kitto sleuthed his social media feed, finding a woman who used the "like" feature on one of his photos on Facebook.
"That's when I messaged her and said I'd been in a relationship [with the serviceman]."
Text messages between the other woman and Kitto show the moment the truth came out.
She wrote to Kitto, explaining: "I've been dating [the man] for a year and a half. This has come as a complete shock as we've been living together the past few months."
Kitto responded: "Living together - [how] is that possible when he's been staying at mine. He's here now."
She then sent a picture of the man sitting in the house.
The woman replied: "I moved to New Zealand to be with him. I'm in shock. I can't believe he is there."
Kitto confronted the man, and the relationship ended.
The other woman did not respond to requests by the Herald on Sunday for comment.
Kitto said her upset over the failed relationships led to her contacting NZDF and making a complaint.
Having spelled out what had occurred, she had visits from military police officers who have since carried out two recorded interviews.
She said questions appeared to be around their disclosures during security vetting processes, which should have included detailing any relationships in which they were involved.
Kitto said she believed the men had "exploited their position and training", either wittingly or without intending to do so.
In the case of the most recent man, military police investigators were also interested in photographs he had sent of his workspace, which she believed to be a classified area.
Neither interview touched on what she said was her concern: that the culture and training of those working in sensitive areas led to hardwired deceptive or manipulative conduct which spilled into their personal lives.
"They were more interested in the security risks. I don't think they are taking the relationship side of things seriously."
Kitto said she wanted a review of training procedures and the culture of highly classified sections of NZDF's intelligence workers.
NZSIS director Rebecca Kitteridge - speaking generally about security vetting and not this case - said those dealing with information rated above "classified" needed a security clearance.
"During the vetting process for a high-level clearance there is a clear expectation for all candidates to provide full and honest information about their personal life, their history and behaviours."
Information was sourced from interviews with those applying, employers, referees and others - including police records.
"If residual security risks are identified that cannot be mitigated, the granting of the security clearance is not recommended."