In 1967, middleweight boxer Rubin 'Hurricane' Carter and John Artis were convicted of triple murder in the United States. They spent almost 20 years in prison, maintaining their innocence, before being released. BBC World Service has investigated the murders - at the Lafayette Bar and Grill in Paterson, New Jersey - in their podcast series The Hurricane Tapes. This is their story.

A triple murder. A guilty verdict. Forty hours of tape recordings from Rubin 'Hurricane' Carter tell the real story

You need a pretty compelling reason to go to Paterson, New Jersey.

It's not what you might describe as a destination city. The litter, the abandoned buildings... it isn't the most welcoming place.

But we were there to visit the scene of one of the state's most heinous crimes.

The Lafayette Bar and Grill, as it was called in 1966, is still open, albeit under a different name. Even at 11am, the bar was doing good business for such a small place. We were slightly nervous as we started talking to two customers, who clutched bottles in brown paper bags, but they told us everything they knew about the case.

It was the first - but definitely not last - reminder that, with this particular case, perceptions and the truth don't often tally.

The one interview we really wanted was the one we couldn't get. Rubin 'Hurricane' Carter - the man at the centre of this story - died in 2014, so giving his perspective was going to be our biggest challenge. Then a friend of his mentioned he knew of some tape recordings Carter had made.

In 2004, Carter had written a book with his friend Ken Klonsky. Somewhere were tapes of Carter talking about the night of the murder, the investigation, and his subsequent conviction. They had never been heard. It was Carter unfiltered, chatting to a friend in the comfort of his own home. A unique insight into the man and his story.

The only problem? No-one knew where the tapes were...

For months we went from pillar to post, speaking to people who knew about the tapes, but not where they were. We gave up hope. Then, out of the blue, we got an email from a man who, while cleaning out his basement, had stumbled on the cassettes. He was sending them to us.

A few days later, a box containing 24 old-fashioned cassettes arrived. Forty hours of Carter. The only problem was how to listen to them. We managed to track down a cassette machine, put it in our studio, and Carter's voice began to fill the air.

We quickly realised that, whatever you might think about Carter, he was incredibly charismatic. "Sometimes I feel like talking," he opens the tapes with. "And I have something to say."

He spoke. We listened.

Another person we wanted to learn more about was the case's lead detective - Lieutenant Vincent DeSimone.

Before his death in 1979, he had actively avoided the media. We tracked down his son, Jim, but he was not keen to speak.

In the Hollywood film of Carter's case, the lead character was portrayed as a racist, corrupt villain. Jim had campaigned against that for many years, to no avail.

Meeting him for breakfast at a pancake house in Paterson was as much as we dared hope for. We talked for a long time about our goals for the project. What we always wanted to do was present as much information as possible for people to draw their own conclusions.

At that point, to our surprise, Jim said he had been given a box after his father's death that was a treasure trove of information on the case. Would we like it?

We jumped at the chance, and soon we had another cassette tape, this one featuring DeSimone's voice. We ended up meeting Jim several times. He's good company - down to earth, and emotional about his father, who he was clearly close to.

Finally, there was John Artis.

Artis was convicted twice alongside Carter, but his story has never been told. We weren't really sure what to expect. What we found was a man with a big, booming laugh; a man who lost his youth but now, in his 70s, is content and comfortable with his life.

For four hours, we sat by the beach in Virginia with John and recorded. He took us for dinner, where we ate too much while looking at the photo albums John kept charting his and Carter's lives.

We had three characters. Two dead, one never given the chance to speak. It was up to us to give them a chance to tell their version of events - in their own words.

Each week, BBC Sport will publish a new article to coincide with the latest episode of The Hurricane Tapes. A longer feature piece on the BBC World Service's investigation will then be published at the end of the podcast series.