You look over the fence and see the River Severn, and the hills of the valley in the distance.

It is a beautiful, peaceful spot, but it is also a place linked to crime, violence and decades of anguish.

Joanna Parrish is buried here, her gravestone written in English and French.

She was murdered 33 years ago hundreds of miles away, in the French city of Auxerre.

Joanna was 20 years old, a university student teaching in France as part of her degree.

She went missing and then, not long after, her body was found in the River Yonne.

Nobody has ever been convicted of her murder, but we know who did it.

A serial killer called Michel Fourniret, who was already in prison for seven murders, admitted to killing Joanna five years ago, but died before he could be put on trial.

But now, after decades of despair and tragic errors, justice may be within sight.

Because Fourniret did not act alone.

He was helped in his murders by his wife, Monique Olivier, who lured girls and young women and allowed them to be attacked, raped and murdered by Fourniret.

She is still alive, now aged 74 and serving a 28-year sentence for complicity in the murders.

She once confessed to seeing Fourniret murder a young woman in Auxerre - clearly Joanna - but then retracted that statement.

Now, though, she is about to go on trial for being an accomplice in three further murders, including that of Joanna.

It has taken a third of a century, but perhaps justice is finally going to be delivered, for Joanna and for the parents who have spent decades searching for a form of closure.

Lives changed forever

At home in Gloucestershire, Pauline Murrell tends to her pet budgie and offers us a cup of tea.

From the sofa, her former husband, Roger Parrish, asks for a coffee.

The pair have been divorced for decades, but are still evidently close, caring and friendly. They finish each other's sentences.

Their lives changed, instantly and horribly, when they were told that their daughter had been murdered.

"It's impossible to take in," says Pauline. "They said she was found in the water, and I was staring out of a window and I simply couldn't take it in. I couldn't cry for six months.

"Then I got the post-mortem report and I opened it on a Sunday morning, and I wasn't able to get out of bed."

Roger wipes away a tear, the memories still so haunting. "She deserved a long and happy, fulfilled life. She worked hard and she deserved it. She was helpful, part of the community. People still remember her. She did well."

Pauline's last phone call with her had ended with a declaration of love from the parents to their daughter. It is a memory that offers some solace.

The devastation of grief was followed by frustration about the police investigation.

Roger and Pauline heard little from the French authorities. Instead, they went to France themselves and started asking questions, looking for information and demanding more effort.

And then came the arrest of Fourniret, and the pieces began to fall into place.

As it slowly became apparent that his wife had helped him, so Roger and Pauline became convinced that he had killed their daughter.

"Jo was a kind person," says Roger, "but she was also bright and smart.

"She was not likely to have trusted a man who was by himself.

"When we found out that there was a female accomplice, I remember thinking that we had never thought of that. Why would we have done? But right from that moment, I thought, 'this is it - this is the person'."

But still the police could not put together the evidence to link Fourniret with Joanna's murder.

In fact, they had bungled the investigation, mishandling the crime scene and mislaying crucial forensic evidence.

French police 'lost some really important evidence'

Bernie Kinsella was a detective who worked as a liaison between British and French police.

He discovered an investigation that struggled to link multiple crimes, or to manage its resources. He's still in touch with Roger and Pauline.

"The French lost some really important evidence," he told me. "The semen sample from the original rape had just been lost, which is unthinkable in terms of any major investigation like that.

"Losing an exhibit like that is a glaring error, so that had a massive impact on their ability to investigate this properly."

Desperate, Pauline even took the step of writing to Monique Olivier.

"I remember just saying that, from one mother to another mother, I wanted to know what happened. Her lawyers said it was a trick, that it wasn't proper, and I was upset about that.

"It wasn't a trick. It was heartfelt.

"It's just such a horrible, horrible thing. I can't imagine that any mother would be able to live with themselves.

"And now she's pushing the victim bit, but I certainly don't consider her the victim." Her voice echoes with contempt.

Olivier has always suggested that she was coerced and intimidated by Fourniret, a claim that has been roundly dismissed by prosecutors.

When she was first convicted, in 2008, the court concluded that, far from being easily influenced, she was highly intelligent and capable.

The convictions of Olivier and Fourniret did not bring justice for Joanna. Olivier had originally made a statement linking her husband to the murder, but she then withdrew it.

The case went quiet and was eventually closed.

But in 2018, 28 years after he killed her, Fourniret admitted to the murder.

A court case beckoned before being delayed by the pandemic. Then, to the frustration of Roger and Pauline, Fourniret died.

"When he died, it wasn't a great surprise because we knew he'd been ill, but we did feel cheated. I wanted to face him in court and that was taken away.

"We're glad that he died. The world is a better place without a person like that but, at the same time, we would have wanted to face him - to look him in the eye."

'Trial is the last hurdle'

Now they have another chance. Both parents will be travelling to Nanterre, just outside Paris, for the trial.

"We probably look on it as the last hurdle," says Roger. "It's been a long time. It's over 30 years so we're glad it's taking place.

"Until it's over, we can't get to whatever will be the next stage of our lives."

Pauline adds: "I keep saying that it's not going to bring her back.

"It's almost as if you feel that once it's over, everything will go back to normal. But it'll never be like that."

"No, it won't be," says Roger, nodding, holding his head.

"But it will stop us having to think all the time about what we are going to do next, what's the next step, what are we going to do.

"Hopefully, that will be it - that it will clear our heads a little bit. We'll never forget Jo. She'll always be there."

Roger and Pauline are warm, charming people, whose lives have been blighted in the most horrendous way.

If Olivier is convicted, it will surely bring some kind of closure.

But you wonder - after waiting so long for something so important, can it ever really be enough?