In the early hours of July 8, 2010, Scott Guy was gunned down at his farm gate. Police suspected his brother-in-law, but he was found not-guilty and no one else has been held accountable for the killing.

Thirty-one year old Scott Guy was on his way to work, it was just a regular day, when he was murdered in his driveway.

He had no known enemies and there were very few clues to point to who might have wanted him dead.

Eventually, police discovered there had been tensions between Guy and his brother-in-law Ewen Macdonald and that Macdonald had committed a string of other crimes in the neighbourhood.

They arrested him for murder, but he was found not-guilty.

Stuff Investigative journalist Mike White discusses why the police case against Ewen Macdonald failed and who else might have been responsible for Scott Guy's murder.

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In 1960, police discovered the body of a man in a central Auckland apartment, but it is the disappearance of his wife, Cynthia Grierson Jackson that has baffled police for more than half a decade.

Neighbours describe one night where there were loud voices coming from the apartment of Cynthia Grierson Jackson and her husband, Michael.

Otherwise, there was nothing to suggest the grisly scene police would discover a couple of days later.

Scott Bainbridge, author of Without a Trace, investigated the disappearance of Cynthia Grierson Jackson and police discovered Michael Grierson Jackson died of blood loss after castrating himself.

His wife has never been found.

The only lead police had is that days before his death, Michael returned Cynthia's uniform to her workplace and told her colleagues she had left him.

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Six people were killed and four injured when Stephen Anderson took his father's shotgun and went on a rampage in the sleepy North Island settlement of Raurimu, in 1997. Michael Morrah interviewed Anderson and tells his story.

When Stephen Anderson saw his parents and their friends eating breakfast at the family bach in Raurimu, he became convinced they were part of a conspiracy to end the world.

His actions led to one of the worst massacre's in New Zealand's history.

Stephen Anderson was found not guilty of the murders or attempted murders by reason of insanity.

He was granted limited release from a psychiatric facility in 2009.

Newshub investigations reporter Michael Morrah interviewed Stephen Anderson several years ago, and describes what was going through Anderson's mind on the day of the murders.

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In the winter of 1954, two schoolgirls - Pauline Parker and Juliet Hulme - murdered Pauline's mother on a remote walking track in Christchurch. Author Peter Graham recounts the events leading to Honora Parker's death.

On June 22,1954, Juliet Hulme and Pauline Parker went for tea and a walk at Victoria Park in Christchurch's Port Hills with Pauline's mother, Honorah Parker.

It was there, on one of the park's remote walking tracks, that the teenage girls brutally killed Pauline's mother.

True crime writer Peter Graham wrote a book about the case called So Brilliantly Clever and he describes how 16-year-old Pauline Parker and Juliet Hulme, 15, became two of New Zealand's most notorious murderers.

Fearing separation, they came to believe Honora Parker was the only thing standing in the way of their being together.

At trial, the pair were found guilty but due to their age and lack of proper holding facilities for them, they only served about five years in prison.

Juliet Hulme later changed her name to Anne Perry and became a successful writer. Both she and Parker now live in the United Kingdom.

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Barrister Simon Shamy describes the tragic murder of Ruby Knox. He represented Donella Knox who admitted killing her daughter.

In May 2016, Donella Knox sedated and then smothered her 21-year-old daughter, Ruby.

She was sent to jail for four years.

Donella had been the sole carer for her daughter Ruby for 20 years.

Ruby was severely autistic and intellectually disabled. She could not speak, was violent and needed constant care.

Mr Shamy said mother and daughter loved each other very much, and had no one but each other.

"The level of pain and suffering that Ms Knox has undergone for 20 years on her own and now for the rest of her life is unparalled in my experience," he said.

In sentencing Ms Knox, Justice Joe Williams described the case as "once in a generation" which made a life sentence manifestly unjust.

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On New Years Eve, 1976, 36-year-old Heidi Charles vanished without a trace. True crime writer Scott Bainbridge explains how this baffling case has been mixed up with other high-profile disappearances.

On New Years' Eve 1976, 36-year-old Heidi Charles was dropped off in central Rotorua to do some shopping.

She arranged to meet her husband, Robert, and two sons an hour later at Fenton Park. But she never turned up.

It was one of the busiest days of the year in the holiday hotspot, but no one has come forward with information about what might have happened to Charles.

There were two possible sightings of her, one in a clothing store shortly before she was due to meet her family and another on the outskirts of town.

Police went to extreme lengths to try to figure out what happened to her, including throwing a sheep carcass into a hot pool.

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In 2011, 17 year-old Emily Longley was strangled to death by her boyfriend.

On the 7th May 2011, Emily Longley was found dead at her boyfriend's house in Bournemouth, England.

The 17 year old New Zealand had moved to England to go to college. She had only been there for eight months.

Emily's boyfriend, 21 year-old Elliot Turner, was eventually charged with her murder and his parents were charged with covering up the crime.

During his trial, Elliot Turner claimed that he acted in self-defence but during sentencing, Justice Dobbs said he had "bullied, harassed, threatened and assaulted" Ms Longley.

Turner must serve at least 16 years before he can apply for parole.

Emily's father, Mark Longley, is Digital Managing Editor and Newshub and he has made a podcast podcast series - Death: Love, grief and hope

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David McNee was beaten to death in his own home in 2003. His killer was found guilty of manslaughter after using a provocation defence referred to as the 'gay panic' defence.

In 2003, Philip Edwards went to David McNee's house to perform a sex show for $120 but ended up killing the well known interior designer.

McNee's killer used a partial 'provocation defence' which was at the time referred to as the 'gay panic' defence.

He was eventually found guilty of manslaughter and sentenced to 9 years in prison.

Law Professor Elisabeth McDonald from Canterbury University has looked into this case and the controversial defence used.

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It's one of the most brazen robberies in New Zealand's history. In November 1956, Auckland mobsters made off with the equivalent today of $1 million after breaking into the Waterfront Industry Commission's offices.

In 1956, Auckland mobsters might have pulled off the heist of the century, after breaking into the Waterfront Industry Commission offices and making off with the equivalent of a million dollars.

In his book The Great New Zealand Robbery, Scott Bainbridge tells the rollicking story of how robbers blew up a safe in the Waterfront Industry Office which was full with the week's wages.

A man named Trevor Nash was eventually arrested, tried and jailed for the offence. Then he escaped and only a stroke of luck enabled police to recapture him.

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The 1992 murder of English tourist, Margery Hopegood, stunned the country.

Margery Hopegood was born in New Zealand but had been adopted by a English family and raised there.

She had been back in New Zealand just four days when she was brutally murdered.

The murder was huge news and the people of Hamilton turned out in their hundreds to a memorial service for a woman none of them know.

Wellington playwright and actor Nicola Pauling has a strong family connection to Margery and turned the full story of her visit to New Zealand into a play called She Danced on a Friday.

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