Graham Dwyer’s bloodletting fetish was never revealed to his wife but his fantasy and bad temper sufficiently disturbed his former partner and mother of his first child for her to leave him and move back to her native Donegal to get away from him.

Security sources said Dwyer’s wife Gemma was not asked about their sex life by the prosecution while giving evidence in his trial because her description of it when aiding the murder inquiry would not have advanced the case against him.

Associates of Dwyer's who have spoken to The Irish Times describe a short-tempered man obsessed with what others thought of him, his level of income against that of others, and about his desire to climb the social ladder away from his working class roots in Co Cork.

From a modest background, Dwyer married into a wealthy family of professional people.

His wife, Gemma Healy, originally from Co Sligo, is also an architect and is the daughter of Dr John Brendan Healy, a Sligo-based trauma and orthopaedic surgeon.

He is a former chair of the Irish Medical Council’s fitness-to-practise committee and is well known and well respected in medical circles. At least one other family member is also a surgeon.

Dwyer has been held in prison on remand since his arrest in October 2013. The couple have been estranged since then.

Dwyer's wife left their home at Kerrymount Close, Foxrock, south Dublin, after her husband was arrested there and it was searched. The house has been empty since. Neither Gemma Dwyer nor the couple's two young children visited him in the 18 months between his arrest and trial date.

Studying architecture

Graham and Gemma Dwyer met while studying architecture at Dublin Institute of Technology, Bolton Street, in 1997, by which time he was the father of a five-year-old boy from a previous relationship. Three years later they bought their first house, at Gulistan Cottages, off Upper Mountpleasant Avenue, between Ranelagh and Rathmines in south Dublin.

They set about redesigning the small cottage, and the product of their work was featured on the front cover of The Irish Times property section in May 2007.

The young couple, now married and in their 30s but with no children, were presented as members of the “trendy architect set” snapping up the “pint-sized” cottages in the area originally built in the 1880s for firemen based at Rathmines station and their families.

They posed for photographs for a considerable spread. The article outlined how they had paid about €200,000 for the two-bed cottage in 2003 and spent €60,000 renovating it into a “smart city pad” before putting it on the market four years later for €590,000 and moving to Kerrymount Close.

Dwyer, just 35 years old at that time, was already a partner in the major A&D Wejchert Architects practice based on Baggot Street in the south inner city. His wife was a project director with DMOD Architects in Dublin 8.

Bandon background

Graham Dwyer was born on September 13th, 1972, to Bandon couple Seán and Susan Dwyer. He was the second eldest and has an older sister. The family expanded after Dwyer's arrival, with two other sons coming along in the years that followed.

Dwyer attended national school locally and appears to have shown academic promise and a strong work ethic from his early days.

After national school he moved to Hamilton High School, also in Bandon, which boasts small class sizes and has a strong focus on academic achievement.

As a teenager, Dwyer was interested in music. He played bass guitar and enjoyed the social life that went with this.

He was, according to those who knew him, confident with girls his own age and was popular with them. He played in a Bandon-based band named Strangeways. Those who studied with him and worked with him knew of his interests in flying and music.

The latter hobby made him a regular concert-goer, and in the summer of 1991 he went to a music festival in Tipperary where he met Ballyshannon girl Emer McShea.

They began a relationship, which continued while both were in college in Dublin and lasted until they were in their mid-20s. McShea became pregnant with Dwyer’s child and gave birth to son Senan in October 1992.

Emer McShea told Dwyer’s trial that when discussing fantasies with him, he confessed to a stabbing fetish, specifically saying he wanted to stab a woman while having sex.

This was some two decades before he was using fetish websites to meet women with whom he could act out his BDSM fantasies, including stabbing them. It was on one such site that he met Elaine O’Hara.

After confiding in McShea about his stabbing fetish three years into their relationship, Dwyer began to bring a kitchen knife to bed and pretended to stab her during sex, though never did.

The relationship ended because McShea was so concerned at Dwyer’s behaviour and bad temper that she moved back to Donegal with her son. She is now married and works as an environmental health inspector.

While Dwyer remained in touch with his now adult son and financially supported him, the relationship with McShea was poor. Dwyer was open about having a son. “It wasn’t a secret, everyone who knew him would have known about the boy,” said a former associate of Dwyer’s.

Around the time his son Senan was born, Dwyer began studying architecture at Dublin Institute of Technology, Bolton Street, in Dublin’s north inner city. He qualified in 1997 with a 2.1 degree.

Sources familiar with his life when at college said there was no indication of his interest in BDSM or his stabbing fetish. “He was fairly charming and he was popular; he could turn it on,” said one source.

“He liked a few drinks like everyone else and he was definitely into the music. He was a bit unusual because he was maybe a year or two older than a lot of the others and he also had a child. He was definitely still into chasing women when he was out though.”

Working life

Dwyer began working in architects’ offices around one year before graduation. In 1998 he became an associate member of the Royal Institute of the Architects of Ireland, the profession’s regulatory and support body. He has been a full member since 2001.

He worked at a number of architectural practices in the early years of his career, including Keane Murphy Duff, Oppermann Associates, and Burke-Kennedy Doyle.

Some of those who worked with Dwyer said he socialised with colleagues outside of the office, but that this had not always gone well. “It would be a lie to say there were signs looking back now, but it was just regarded as rows or temper at the time,” said one source.

On one occasion, Dwyer’s employment was ended after he became involved in an argument with a colleague while socialising. When people arrived into the office the following Monday morning, the person with whom Dwyer had clashed found their workstation thrashed, including their computer.

A process was begun against Dwyer and his tenure with the firm was brought to a close. So concerned was management about his behaviour, specifically the swings in his mental state, that they changed the locks to the building so he could not gain access.

On another occasion, he hacked into the internal computer system in one office to determine how much those around him were earning. “He went absolutely spare when he realised that some people were being paid a lot more than him,” said one source.

Another said: “He was definitely into money and status symbols. Buying a house in Foxrock, of all places, would be typical. But it was just as much about what everyone else was earning compared to him.”

Other colleagues said he had a tendency to drink too much when socialising, describing him as a womaniser when he had consumed alcohol. “He would go for what he perceived as easy prey; maybe women who were overweight, not that socially confident.”

However, most of those who knew him regarded him as clever and charming. He was particularly good with computers - his wife telling his trial he could do anything with them.

David Lanigan, director at Polish-owned architectural practice A&D Wejchert, told his former colleague’s trial that Dwyer was “particularly skilled” at 3D visualisation and artist’s impressions, and was “very skilled” with computers.

He was also interested in cycling and mountain-biking. He sometimes cycled to work from his home in Foxrock and went mountain-biking in Co Wicklow, meeting a group for the purpose at the Hellfire Club.

He also enjoyed camping. But the biggest hobby in his life was flying model aircraft. He worked on them almost every day, regularly ordered parts for them from specialist websites around the world, and flew them in races almost every weekend.

His interest developed properly at a flying club in the Phoenix Park and then in Shankill before joining Roundwood Model Aeronautical Club, a club for advanced enthusiasts, in Roundwood, Co Wicklow. He was also a member of the Model Aeronautics Council of Ireland and Shankill Radio Flying Club.

As well as flying the planes at weekends, he would also sometimes go on Wednesdays and Thursdays straight from work, while his wife would use her free time to go sailing in Dún Laoghaire.

Dwyer told gardaí he was especially close to his son. His wife and former colleagues gave evidence suggesting he was a “new man” around the house; outlining how it was he rather than his wife who rushed home to let the childminder go in the evenings and that he took care of paying her.

In 2001, Dwyer’s career took a major step forward when he joined A&D Wejchert, and he was still working with the firm at the time of his arrest on suspicion of murdering Elaine O’Hara.

He became an associate in the company in 2003 and was promoted to partner – one of five – three years later.

He worked on a number of major projects with the company, including the stadium at Leopardstown racetrack in south Dublin, the student centre in Carlow Institute of Technology, a major development plan at UCD, and a mall in the Blanchardstown shopping centre in west Dublin.

He also represented the company at major events, including a hearing about the redevelopment of Liberty Hall in Dublin’s north inner city and receptions at the Polish embassy, as well as on trips to Poland, the homeland of his employers.

Financial background

Documents seized from his home showed his salary was cut in the space of six months in 2011 from €87,000 to €70,000, but that a €13,000 pension premium was also paid to him at that time.

There was evidence that the cut to salaries at the firm from 2009 to the present was 50 per cent. This suggests Dwyer earned in the region of €140,000 per year at the height of the boom, though this was never outlined in court.

His wife had gone through a redundancy during her career, and while she had found another job, a picture of a family short for money emerged in court.

He told gardaí in interviews that he was “very poor” and that when he celebrated his 40th birthday in September 2012 he received a guitar as a present and that everyone had chipped in for a meal in a restaurant in his native Bandon.

Twelve months to the day later, while he and his wife celebrated their shared birthday of Friday, September 13th, in a Dublin restaurant, gardaí were sealing off an area on Killakee mountain, Rathfarnham.

A dog walker had that afternoon found bones, later confirmed as those of Elaine O’Hara’s.

Dwyer had sold two bicycles because he was short of money, and had also regularly bought and sold cars.

In the earlier years the family had usually gone on holidays to Lanzarote. Dwyer also had a preference for fast and expensive cars.

He once had a Porsche 911 which he called his “baby”, and had also owned two Audi A3s, an Audi 6 estate, Audi A4 estate and an Audi TT.

All the while he was leading a double life, visiting sites such as alt.com and fetlife.com, and using names like architect72 and Fetishboy while his wife suspected nothing.