On 9 June 1984, 17-year-old Melanie Road was found dead, the victim of a crazed knife attack.
It would take 32 years for her killer to be brought to justice.
Now her story is being told like never before in a new podcast from ITV News which hears from the detectives involved, and Melanie's family.
It describes the wrong turns, the false leads and fading hopes of a group of detectives who were told by a chief constable to drop the case.
But it culminates in a moment of courtroom drama when Melanie's family confront the killer and lay bare what it's been like living with unanswered questions for three decades.
Here, Robert Murphy tells the inside story of the case which captivated him.
I remember the conviction that one day there would be a conviction.
It was June 2014 and I was interviewing Detective Inspector Julie Mackay who was making a press appeal on the 30th anniversary of a murder about which she obsessed.
The stabbing to death of 17-year-old Melanie Road in Bath in 1984.
It was one of the highest profile murders of that year. One of the biggest manhunts in Britain.
And it seemed so solvable, Detective Inspector Julie Mackay told me. Avon and Somerset Police had a trail of the killer’s blood leading from the scene. A full DNA profile of the murderer too.
All Detective Inspector Mackay had to do was link the DNA left at the scene with a man who may well have gone on to lead a seemingly normal life.
Who was this man? Where on the planet was he? Was he even still alive?
This was one of those cases which, when you heard about it, immediately drew you in.
Julie was the latest lead officer to take it on - she’d been running the inquiry for five years. But every detective who came near the investigation became hooked on the details from 1984.
One of the original lead detectives had even gone to his own grave, the one regret of his career being he was unable to find this killer.
So while I admired Julie’s insistence that she would find Melanie’s murderer, I was unsure exactly how she would do it.
Neither I – nor she – knew could have predicted the dramatic developments which were just a few months ahead and would lead to police closing in on the killer.
I was in the ITV newsroom when I got the message that a man had been arrested. And I recalled immediately Julie’s conviction.
But I had no idea then of the behind-the-scenes dramas. There was a moment that weekend when the killer very nearly walked free from police custody because of a technicality.
The thing that would later strike me the most was how inappropriate the phrase ‘cold case’ was for this.
I interviewed first Melanie’s mother, Jean, and then her brother, Adrian. Two of the most articulate, dignified and thoughtful people I have met.
And even though their Melanie had been killed more than 30 years before, to her mother and brother, it may as well have been yesterday.
The moment Jean, Adrian and Melanie’s sister Karen confronted Melanie’s killer in court was, without doubt, the most emotional moment I have seen from a press bench.
They each delivered 30 years’ worth of eloquent anger at her killer. None of them spoke with any vengeance, they were each collected. But that magnified the power of their words.
It was only when I recorded new, in-depth interviews with Julie and her team that I realised how unique this case is. The twists and turns were incredible. The false leads and fading hopes.
But what brought Melanie’s killer to justice was the work of the team. Their conviction really did lead to a conviction.