In one sickening wave after another, the details of Elaine O'Hara's murder trial kept coming earlier this year. Yet it was only afterwards that one of the more unsavoury and bizarre details of the case emerged: that Graham Dwyer, convicted of her murder in March, has been sent several 'fan' letters at Cloverhill Prison, along with lingerie and BDSM masks. Neither prison staff nor psychologists were remotely surprised at the development, with many commenting that this was far from exclusive to Dwyer's case.

But for a number of Irish women who regularly write to convicted killers, romance is seemingly the last thing on their minds. 20-year-old Angel Cullinane, a Belfast-born student now living in Dublin, said that she started writing to prisoners on death row in the US out of curiosity.

“I was driving past Magilligan prison [in Derry] and said to my mum, ‘would I ever be able to contact someone in there?’ ” she recalls. “It was a beautiful day, and I remember feeling that I was so near these people, but they had a very different perception of the world. I’m a very nosy and curious person anyway, and I didn’t want to be ignorant about such a big thing in the world. It’s made me think a lot about how I live my life.”

After conducting some internet research, she came across Lifelines Ireland, an organisation that pairs up pen-pals with overseas prisoners. Last September, Cullinane started writing to Paul (not his real name). Now 51, Paul has spent 21 years on death row in Florida for the rape and murder of an 80-year-old woman.

“I was warned that a lot of responsibility comes with writing to a prisoner because in many cases that’s all they have,” says Cullinane. “So I wrote to Paul and said, ‘I’d love to get to know you if that’s okay’. He wrote back that he’d love to build a friendship, but that he’d had a pen-pal for 20 years who had recently died of breast cancer so he was a little nervous of building another friendship. It had hit him quite hard.”

But the two found their groove via letter writing, and now they correspond regularly on everything from her family and studies to his ongoing appeal. Cullinane quickly realised that, much as the title of the organisation that she approached suggests, the correspondence often becomes a lifeline for those who spend 23 hours a day in a 6ft by 8ft cell, without TV, internet or radio.

“He was convicted but he didn’t do the crime,” asserts Cullinane. “He’s fighting to get three of the charges dropped. He is on his last appeal, and will represent himself in court. ‘No-one will fight for your life the way you will,’ he says.

“I’m not there to judge him or to fight for him,” she adds. “We talk about it and he sends me articles on how the system works. We send each other poetry, too. I’ve asked him what he wants to do when he gets out. He says it’s hard to get a job with a criminal record, but he will survive.”

It’s easy to see what Paul gets out of the exchanges, but Cullinane is adamant that the experience is every bit as gratifying and enriching for her.

“I was so humbled by the first letter I received,” she recalls. “It’s a really special thing to hold in your hand. I get really excited when the letters arrive. It’s exciting to get that insight into a person’s life.

As to how her nearest and dearest feel about her writing regularly with a fiftysomething man convicted of rape and murder: “My mum was a bit dubious and worried for me,” admits Cullinane. “She knows I want to do it so she’s standing back and not saying much. She doesn’t want to ruin the experience for me. My dad thinks it’s great though, and my boyfriend is the same.

Predictably, others have waded in unbidden with their opinions. "A lot of my friends on Facebook say things like, 'he deserves to die'," says Cullinane. "A mature student in my class warned me that a lot of women write to men in prison for dating purposes, that it can get very intense and serious and that a lot of men would take advantage of me for money. She assumed I would be 'caught out' because I was young and naïve. But I do understand the risks associated with it."

According to Pauline Gavin, chairperson of Lifelines Ireland, Cullinane is one of around 150 Irish members that write to prisoners abroad. Of these, three-quarters are women.

“No-one ever is looking for romance our end,” she explains. “Some people might hope for it on the inmate side but so far as I know it’s never happened with the Irish members. I could be wrong, but people don’t usually keep us up to date on how their relationship is going.

“Usually [people write to prisoners] to make a difference to someone who has very little or no contact with the outside world,” she adds. “Death row brings with it a kind of loneliness most can’t begin to understand, and the thought of spending one’s life like that is horribly daunting. When people ask us for a penfriend, they usually say they’d like to befriend someone to help take away the pain of that loneliness.”

Gavin herself joined the organisation 20 years ago, initially as a penfriend.

“I got a guy from Florida straight away when I joined and I’ve only heard from him once or twice,” she explains. “I kept writing anyway. You’re supposed to keep writing even if you don’t hear from your inmate, as they may be out of pens or stamps and saving up to write back. But it gets very disheartening when you’re writing and you’ve no idea if your friend is even getting your mail.

“It’s rewarding but it’s also a responsibility,” she adds. “It’s enriching and you learn a lot about people, you never know what they’re going to tell you next. Their lives are usually so different to mine. Some people grew up in horrible circumstances and could never have been expected to stay away from crime forever, while others had a good start and just got into drugs and all that mess.”

Patricia Kavanagh, who lives in Kildare, toyed with the idea of writing to death row prisoners for many years before finally filling out the application. She was assigned a prisoner straightaway. Brian (not his real name), a death row resident of some 20 years, had 'been left hanging there' after another Irish penfriend failed to correspond.

“Some well-meaning people said, ‘don’t give out your home address … what if he gets out and lands on your doorstep?’ ” she recalls. “I tried to put all that aside and see the person separate to the crime he had committed.

"I'd forgotten the art of writing a letter," she adds, recalling the first time she put pen to paper. "I introduced myself and kept it quite light. I was thinking of someone sitting in a 9ft by 6ft cell, so you can't really be gloating about appreciating the beauty of being in Donegal. I mentioned my children and my life, but I didn't tell him too much about my own background. This might sound terrible, but I set up boundaries around what his expectations were. I wanted to make it clear I wanted nothing other than a pen-pal. You do hear stories about women writing to prisoners and then they go out and meet them, all that crap."

Certainly, several high-profile criminals just like Graham Dwyer have attracted legions of zealous admirers. Peter Sutcliffe, a man known as the Yorkshire Ripper, who murdered 13 women, received dozens of love letters following his arrest. Likewise, Josef Fritzl and Ian Huntley have received plenty of fan mail. Charles Bronson, Charles Manson and the Menendez brothers have received marriage proposals (Lyle Menendez, convicted of murdering his parents in 1989, went on to marry two of his pen-pals).

"It is obviously an individual choice, but many women who write to prisoners share a couple of core characteristics," observes forensic psychologist Patrick Randall. "My big question is, 'are they likely to be lonely or tend to be very mothering of others?' This might make them vulnerable to exploitation. Some people are masters of lost causes and they go around looking for problems to solve. From a prisoner's perspective, they are accessing external resources, whether they be emotional resources or legal campaigning for their freedom.

Yet it becomes clear that, much like the other penfriends, Kavanagh’s reasons for registering with Lifelines are deeply rooted in simple altruism.

“I didn’t want to get into that kind of [romance] thing,” she says. “But it is one small thing I can do to give back. I’ve been on my knees in life two or three times, but you lift yourself up if you’ve got children. I feel grateful to be alive today. I had taken a lot for granted before, but your eyes are really opened when you nearly lose something.”

There’s little doubting that Kavanagh’s heart is very much in the right place, but still, it’s hard not to acknowledge her penfriend’s heinous past.

“He’s not there for nothing,” she muses. “He deserves to be there, but he’s a human being who took a wrong road and is now paying the price. And really, who are we to judge?”

That Brian’s fate constantly hangs in the balance is something that casts a long shadow over their correspondence. “I try not to think about it,” she admits. “I imagine it will be upsetting, but I comfort myself with the idea that in some small way, I give a little bit of hope and brightness to their days.”

Donegal-based Mary Stewart, by now a seasoned veteran of letter writing, has corresponded with a number of prisoners down the years. Stewart started writing to death row prisoners, owing in part to a keen political acumen and her strong sense of spiritual faith.

“Only for my faith I wouldn’t be doing this, but I feel very agitated about rights, with regard for life,” she explains.

“When Billy [not his real name] was executed in 2004, I started writing to James [not his real name], who was in the cell next to him,” she recalls.

"[On the day of Billy's execution] Gerry Ryan rang me to say that he'd gotten a stay of execution for a couple of hours, because he had interviewed me a few days earlier," she recalls. "I knew that a priest had visited him, but then I was told that he had been executed by electric chair. He said he would be waiting for us at the gates of paradise. We had a vigil in the chapel in Donegal town at the time."

James was convicted of murdering his wife, her parents and a customer at his furniture garden store in 1975. He has protested his innocence since then and lives on death row in Florida. Florida has around 400 death row inmates, and is second in numbers only to California. He and Stewart have corresponded for almost a decade.

Cullinane, meanwhile, dreads the day that Paul runs out of legal options and inches ever closer to death.

“He is convinced he is not going to die,” she says. “We don’t talk about him dying because we focus on the fact that he’s innocent. But I am afraid that one day he’ll write and say that his last appeal didn’t go well.”

Undeterred, Cullinane is hoping to visit Paul when she goes to the US on a J1 visa next summer.

“I would regret it if I didn’t,” she reflects. “He’s incredibly strong, and it’s amazing to have that influence in your life.”

For more information, see lifelinesireland.org