The green fields and high hedgerows in the Wexford countryside around the villages of Castlebridge, Screen and Curracloe must have felt utterly alien to Joseph Maskell.

Born and bred in the blue-collar city of Baltimore, Maryland, Maskell found himself in his mid-50s - after a completely urban life - in the rural heartland of the country of his father, who hailed from Limerick.

He arrived in this south-east corner of Wexford in 1994 and lived in Castlebridge - just a few miles from bustling Wexford town - but he would have been familiar with the pretty churches that were a short drive away, such as St Cyprian's in Screen and St Margaret's in Curracloe.

And it was in one of these churches, in April 1995, that he first came to the attention of the Diocese of Ferns. The file does not confirm whether it was in St Cyprian's or St Margaret's that Maskell - a Catholic priest - said Mass in place of Fr Frank Barron, who had been seriously ill, but word reached the bishop's office and it immediately sought a response.

"I wish only to offer Mass privately and carry out my spiritual activities in a like manner," Maskell wrote, adding that the had been granted temporary leave from his last posting and had no "plan or desire to engage in any public ministry while here". He did not respond to a follow-up letter from the diocese seeking confirmation of his status. Fr Barron died shortly afterwards.

A red flag was immediately raised. Normally, a visiting priest makes themselves known to a diocese, but Maskell - who had been seen in full clerical garb in public - did not. And it soon emerged that he was working as a clinical psychologist for the regional precursor to the HSE - the South-Eastern Health Board - at its centre on Grogan's Road in Wexford town.

On June 24, 1996, Ferns contacted the Baltimore Archdiocese only to be told it had no knowledge of Maskell's whereabouts. It was then that the Irish diocese discovered the litany of shocking allegations that had surfaced regarding the seemingly innocuous-looking priest. And yet, he seemingly continued to work as a psychologist in private practice at an address at Common Quay Street, Wexford town, and in Castlebridge, until at least early 1998.

A sobering documentary

A suspected paedophile and serial abuser of teenage girls, Maskell is the subject of a new critically acclaimed documentary Netflix series, The Keepers - and it has thrown his three-and-a-half years in Ireland, between 1995 and 1998, into sharp relief.

The series documents the years of painstaking work by former pupils at the school where Maskell was employed as chaplain and it makes for sobering viewing. Not only does it focus on allegations of prolonged sexual abuse of young girls at a school in Baltimore, it also looks into an unsolved murder case.

Maskell, the programme alleges, systematically abused pupils at the Archbishop Keough High School in the 1960s and, possibly, right until he left the school in 1975. And he is suspected by the makers of The Keepers as the most likely killer of a young nun who taught at the school, Sister Catherine Ann Cesnik.

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Sr Cathy, as she was known, was a universally admired teacher who, at 26, was seen as one with a special connection with her students. One of the girls at the school, Jean Wehner, has testified that she confided in the nun about the abuse she was experiencing and that Sr Cathy assured her she would make it stop.

Shockingly, the same witness says Maskell later drove her to the remote outdoor site where Sr Cathy's lifeless body lay, and warned her that such a fate happened to people who said "bad things" about others.

The young nun went missing from the flat she shared with another nun in November 1969. She had left home to buy a present for her sister. Her body was found two months later. She had suffered massive trauma to her head. The case of her murder remains unsolved. Maskell's body was exhumed earlier this year to check if his DNA matched the crime scene. It did not.

A charismatic man

This week, few people in Wexford could recall Maskell's time there. "I don't remember him at all," says a farmer from Curracloe, "and it would have been unusual enough 20 years ago to see someone you didn't know at Mass, let alone saying the Mass, but since the news, it has jogged the memories of some people and they say they remember an American priest who lived in the area around that time, but he seems to have kept himself to himself.

"When I heard about the things he did in America, I'm not surprised he didn't want to draw attention to himself or get too close to anyone."

Others have vague recollections, including a pensioner who's a native of Castlebridge. "I haven't seen the programme, but I read about it in the Wexford People," she says. "It's awful to think of someone like that living among us back then.

"I have vague memories of an American man from the time and when I talked to my neighbours about it, nobody has a clear memory of him. One was sure he used to call himself Anthony, so maybe he was using a false name."

Priest who came to Ireland in 1990s linked to nun's murder in new Netflix documentary The Keepers 

In fact, Anthony was Maskell's Christian name. He was born Anthony Joseph Maskell in Baltimore City on April 13, 1939, but chose to call himself Joseph - the same name as his brother, and in deference to St Joseph - when he first went into the seminary. He was ordained a priest in 1965 and became chaplain both at Keough High School and the Baltimore County Police, where his brother was a policeman.

Maskell was a charismatic and urbane figure with an imposing manner. Everyone who came in contact with him, including a psychology professor who lectured him when he was in middle age, talks of a deep intelligence. He had a fascination with psychology and offered his services as a counsellor to pupils. It was a useful skill for one keen to identify vulnerable pupils - and their testimonies showed he exploited it ruthlessly.

In a sinister twist, the girls would be summoned to Maskell's office from their classrooms over the PA system. It was a call they came to dread, particularly as they said Maskell tried to normalise the abuse with some while also threatening others whom he feared would tell on him.

Some of his victims were too young to fully understand what he was doing, especially as he was regarded as such an important authority figure who was doing God's work, and he had been so visible in the community, officiating at baptisms and other important events in the Catholic community.

What makes the tales of rape and humiliation especially heart-rending is the fact that so many happened during the course of a normal school day. The location of Maskell's office - at the end of a corridor - meant he could conduct his business without having to worry about passing traffic outside his door.

Fr Neil Magnus, another priest at the school (also deceased), is said to have helped in one instance when Jean Wehner told him in confession that she had been abused by her uncle. She said Magnus raped her and then Maskell took her on to "cleanse" her of her sin. His method was the repeated rape of the teenager.

The case against the Baltimore Archdiocese

Twenty years later, Jean Wehner went public. She had married and had children and had somehow repressed all the awful memories of her time in school. But the ordeal came back to her.

She was one of two women - code-named Jane Doe and Jane Roe - who took a $40m case against the Archdiocese of Baltimore. Maskell denied her allegations and the Archdiocese - through a trio of top lawyers - said they lacked corroboration for her story (something The Keepers argues is not true).

Around this time, Maskell was sent by the diocese to a facility called the Institute for Living in Connecticut for "treatment", but after just six months, he was allowed back into ministry in 1993. He left for Ireland the following year, when police started investigating him for the murder of Sr Cathy.

A total of 30 women have come forward with allegations of abuse by Maskell. The Baltimore Archdiocese has given financial compensation to cover counselling for 16 victims of his abuse.

One of those victims, Teresa Lancaster - who's now an attorney helping those who have experienced sexual abuse - says she has heard that there are Irish victims. "We do have word that there are two victims coming forward in Ireland," she said, in an interview with an Irish newspaper.

Questions will be asked about how a man who was subject to such a serious investigation in the US could be given garda clearance to work in an environment where he would have access to teenagers.

'A lovely man to deal with'

John Cooney, the former head of the South-Eastern Health Board, says it is almost certain that not only would Maskell have counselled young people ,but he would also have dealt with those who were victims of sexual abuse. "Children were referred to him for counselling," he said at the weekend. "He wouldn't have much access to adult patients when he was working for us, it was mainly the child welfare service."

The Wexford People's Maria Pepper tracked down one woman whose child had been psychologically assessed by Maskell. "Our daughter was eight years old at the time and saw him through the South-Eastern Health Board," she told the newspaper. "We were shocked to hear all these allegations about him. We can't believe it. He was a lovely man to deal with. It just goes to show that the bad guys can wear the mask of the good guys.

"We didn't know he was a priest until after the assessment when someone told us. He signed his report A Joseph Maskell, Clinical Psychologist."

Maskell arrived in Ireland at a time when the spectre of clerical sexual abuse had become a constant on the news agenda. After decades of rumour and hearsay, the behaviour of some Catholic clergy and the blind-eye turned by select bishops started to come to light, and victims, like Wexford man Colm O'Gorman - now head of Amnesty International in Ireland - started to tell their harrowing stories.

It is not known why Maskell chose Wexford when he fled the US, and there is no suggestion that he knew the then bishop, Brendan Comiskey. But this week, some are questioning the "coincidence" of him choosing a diocese that would soon become notorious for the number of priests who abused there and how Comiskey consistently failed to take action.

The disgraced bishop emeritus, now 82, took a dim view of those who questioned him, and former Irish Independent journalist Justine McCarthy has written that a drunken Comiskey threatened to "come up to Dublin and rape you" when she confronted him with allegations.

"Even today when people hear the word 'Ferns', their thoughts turn straight to Brendan Comiskey and priests like Seán Fortune [Colm O'Gorman's abuser] and Donal Collins," says a priest who ministers in Wexford town, but does not wish to be named. "It's something that will characterise the diocese for a long time and now there's talk of this man, Maskell, coming here too. You would hope there will be a thorough investigation of his time here, and if there are any victims, they will be given the support they need."

It is especially macabre to think that when Maskell first turned up in Castlebridge, Fr Donal Collins - who was charged in 1995 with 21 counts of indecent assault - was living just up the road in Curracloe.

Collins, who had been principal of the boys' secondary school, St Peter's College Wexford, had a fixation with genitalia and was taken with measuring the penises of his victims. In Baltimore, witnesses said Maskell was also obsessed with 'inspecting' the pelvic area and encouraging victims to have pregnancy tests. One stomach-churning anecdote from The Keepers centres on him 'helping' a victim to take vaginal douches.

Could the two men have met in the mid-1990s? Did Maskell have as much ease at identifying and befriending fellow abusers as he appeared to have in the US?

Such questions may take a long time, if ever, to answer. Joseph Maskell returned to the US in 1998 and died of a stroke on May 7, 2001. He was 61 - and he took many of his dark secrets, including his activities in Ireland, to the grave.

But with the HSE investigating his time here and The Keepers bringing his dark deeds to the world, we are likely to know far more about Fr Anthony Joseph Maskell than he would have wished for when he tried to go about his life in Wexford two decades ago.