When Phil Nisbet died in May 2009, the empty pill packets made it seem like suicide. But his sister, Lee-Anne Cartier, soon began to suspect her brother's wife, and eventually presented the police with evidence they could not ignore.
"His biggest fault was that he trusted people too much," says Lee-Anne Cartier. "He didn't see that there were bad people out there or that people would do the wrong thing."
Her brother Phil was the oldest of the four siblings, while Lee-Anne was the youngest - there were two other boys, Andrew and Roger, between them.
She remembers riding on the back of Phil's motorbike, as he took her to Girl's Brigade, when she was only eight years old.
He was the "goody-good" of the family, she says. "He didn't go to a pub until he was 21."
That was 40 years ago, in New Zealand. Later most of the family went to live in Australia. But Phil stayed behind. He was 47 and had been working as a lorry driver in May 2009, when Lee-Anne received a devastating phone call from her father.
He told her Phil was dead. He'd been found in his lorry, and police believed he had killed himself.
"I broke the news to Andrew, and that was the worst," says Lee-Anne. "When I finally got hold of him and told him to make sure his son was in another room, he just shrieked."
She couldn't understand what would have driven him to this.
"It was just so strange. I hadn't had anything to do with Phil for a couple of years, so I didn't really know what was going on in his life, and I was just thinking, 'What the heck's happened?'"
The autopsy showed Phil's body contained high levels of an antihistamine drug he was known to be allergic to, and at that point, Lee-Anne felt she had to accept the theory that it was suicide.
"We had nothing else to go on," she says. "You're in such shock. You're just absorbing what everyone's saying."
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Lee-Anne helped to arrange the funeral and travelled to New Zealand to say goodbye to Phil before he was cremated, but Phil's wife, Helen, refused to leave her alone with him.
The relationship between the two women had broken down in 2006, while Lee-Anne's son, Lance, had been staying with Phil and Helen in New Zealand - the teenager had upset Helen, who called Lee-Anne to complain, resulting in a row.
"It's really hard to say goodbye when you've got things you really want to say - because we lost those couple of years - when the woman who had caused the rift between us is standing there," says Lee-Anne.
Since the rift she had only seen her brother once, when he and Helen had been visiting their mum and dad in Australia, a couple of months before he died.
Lee-Anne had never been keen on her sister-in-law.
"Initially I met her in 2004 and she just seemed your average housewife-type person," she says. "But the next time I met her I sort of realised that she wasn't totally stable."
On one visit to New Zealand, Lee-Anne visited her brother's house and found Phil "freaking out", she says.
"Helen had actually tried to overdose herself with insulin, to kill herself, or so she had told Phil," Lee-Anne says. "I went in to talk to her and she's going, 'I may as well die,' and I could tell it wasn't the first time she'd pulled it."
Then when Lance was staying with Phil and Helen in 2006, Lee-Anne sensed that Helen was behind another bizarre conversation between Phil and Lance in a pub.
It was all about Karen, Phil's first wife, and the mother of his youngest son, Ben.
"Phil actually asked Lance if he could find a hitman to take out Karen, Something like a house fire so it looked like an accident," says Lee-Anne.
"Lance raced home, rang me in Australia very distraught, and I said: 'Ignore it, don't have another conversation with them about it.'"
Lee-Anne thinks Helen still saw Karen as a possible rival and wanted her out of the way. But at the time it all seemed so far-fetched she didn't alert the police.
After Phil's death, Lee-Anne began to have more contact with Helen, and was startled when she told her Phil had died in his bed - not in his lorry, as she had originally been led to believe.
Then, after the funeral, when Lee-Anne was already back in Australia, Helen called to say she had found a suicide note.
"The suicide note that she read me said that he'd found out his son, Ben, wasn't his son, and he couldn't face him again," Lee-Anne says.
Helen also told her that the funeral director had taken a DNA sample from Phil, and that the results showed there was practically no chance that Ben could be Phil's son.
If this had been true, Ben would not have been entitled to any money from Phil's life insurance policy, Lee-Anne says.
Soon after this phone call, Lee-Anne flew back out to New Zealand, because her son, Lance, was holding his 21st birthday celebration there. Lee-Anne stayed with Helen at her house, and on the first night of the stay, Helen showed Lee-Anne the suicide note.
"I open the note and it's typed," says Lee-Anne. "So that's my next shock, and I don't overly read it, but I look to the bottom and there's Phil's signature and it wasn't Phil's handwriting. So I just started sculling my drink and going to myself, 'Oh my God, she's killed him.' That's where all the puzzle pieces just fell into place."
In the same instant Lee-Anne also realised she might be in danger.
"I was just screaming on the inside and sort of paralysed as well, thinking: 'I can't let her see that I know.' I'm just sitting there going, 'What do I do, what do I do?'"
She poured another stiff drink, went to her bedroom and put the suitcase up against the door. The house was out of town. It would have taken her an hour to walk to anywhere safe and she knew that if she left now, Helen would know she had discovered the truth.
She tried to text her boyfriend in Australia, but found she had insufficient credit on her phone.
She was trapped, and alone.
"I was sure she wasn't going to do something to me because you can't have two dead people show up in your house," says Lee-Anne. "My children knew where I was, that was a bonus, but it was pretty scary."
The next day Lance's birthday celebrations were taking place, and Lee-Anne had to make a difficult decision.
"I felt like I was betraying my son, taking her there," she says. "He had always been so close to Phil, growing up, and I took his uncle's murderer to his 21st - but I couldn't not."
"I'd decided that I was going to play her along at this and see what evidence I could collect to take to the police that week.
Lee-Anne took the news about the suicide note to the officer who had originally dealt with Phil's case. He shared her suspicions. People do not type suicide notes, he told her, and passed the information on to some other officers.
Lee-Anne then returned to Australia and told the rest of her family what she had found out.
Her next step was to speak to the funeral director who had supposedly taken a DNA sample from Phil's body. He vehemently denied the story.
"There was some nice swear words there and he was prepared to take her to court," says Lee-Anne.
She then arranged for a real DNA test to compare samples from her parents and from Ben, proving that Ben was indeed their grandson.
Lee-Anne then spoke to Helen's work colleagues - and what they told her was staggering.
"They'd called her the 'black widow' behind her back," she says. "She'd asked them about rat poison. She said to one who'd done some work at the house, 'Don't worry about Phil, he won't be around for long.'"
While carrying out this detective work, Lee-Anne tried to prevent Helen suspecting that she knew the truth. She had to remain friendly, asking about her health and replying to her messages. But one day it all became too much.
"The stories just got so big, and I lost it with her. And I told her that I knew she'd killed Phil and that was the end of getting any more information out of her," Lee-Anne says.
All the evidence Lee-Anne found she passed to the police. But, to her amazement, they took no action and Helen remained free.
The year after Phil's death, though, Lee-Anne discovered she could request an inquest at the coroner's office.
"We had a meeting with the coroner beforehand and I took evidence to show that it wasn't Phil's signature on the suicide note," says Lee-Anne. "And when she opened up her paperwork to show me the suicide note she had, it had been retyped and there was no handwritten signature - and I broke down. So at the actual inquest I questioned Helen on that and other matters."
That was in November 2010. Then came the long wait for justice.
Six months later the coroner's findings were published.
"I consider that on the facts as established by the evidence before me, I am unable to reach the threshold required for a finding of suicide," she wrote.
At this point the police re-opened the case, and Lee-Anne once again presented them with her evidence.
"My only concern was, was it going to be too late to find evidence to the standard of taking it to court and proving it," she says.
But Helen was arrested and charged not only with murder, but two cases of attempted murder, stemming from two earlier unsuccessful attempts to kill her husband.
The trial finally took place in December, 2013, with Helen in the dock and Lee-Anne facing her in the witness stand.
"I'd been told that, being a witness, the defence would use the stance that I had a vendetta against her, and I'd pretty much set her up for it," says Lee-Anne.
These predictions turned out to be correct. The cross-examination she faced was intense - and there was relentless attention from the media.
On the final day, when the jury was deliberating its decision, Lee-Anne and her family rushed to the courtroom, bringing Phil's ashes with them in a casket, to hear the verdict.
On the first count of attempted murder - Not Guilty.
On the second count of attempted murder - Guilty.
On the charge of murder - Guilty.
"I just cried because it was just such a relief that after such a long fight we'd got what we needed - the truth," says Lee-Anne.
To mark the moment, Lee-Anne's son Lance played one of Phil's favourite songs on his phone - Two out of Three Ain't Bad, by Meatloaf.
Helen received a life sentence, but can apply for parole after 17 years.
The police praised Lee-Anne for her detective work and offered her an apology for the failures of the first investigation.
Lee-Anne is now studying criminology in the hope of helping others negotiate problems with the criminal justice system in future.
She still misses Phil terribly.
"Whenever there was a family birthday, or other gathering, Phil would make the pavlova," she says. "So whenever I make a pav I think of Phil and I think, 'This was his thing - I shouldn't be doing it. He should be here, showing up with the pav.'"
And why did Helen Milner kill her husband? Lee-Anne thinks it was financial greed that motivated her - and in particular the prospect of a $250,000 life-insurance payout.
"As my daughter said one day, 'Why didn't she just do the right thing and divorce him?'" Lee-Anne says.
"But it was never about that. Her whole life had been about money."
Listen to Lee-Anne Cartier speaking to Outlook on the BBC World Service
Lee-Anne has written a book about her experience called The Black Widow.
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