A Central Criminal Court jury was satisfied he had lured her up the Dublin mountains on August 22, 2012, to stab her in pursuit of sexual gratification before disposing of her belongings to make it look like suicide.
He had arranged for her to leave her car at the graveyard in Shanganagh where her mother was buried.
His plan almost worked and, in the words of the prosecutor, it was “very nearly the perfect murder”.
The pair had been in a sexual relationship involving stabbings, on and off from late 2007. They rekindled the relationship in 2011 and arranged to meet on the evening Ms O’Hara disappeared.
She had been discharged from a mental health hospital hours earlier.
A dog uncovered her skeletal remains in the mountains at Killakee on Dwyer’s 41st birthday, Friday, September 13, 2013.
It was three days after her keys had been found in the almost-dry Vartry Reservoir in Roundwood, Co Wicklow.
During the nine-week trial, the jury heard from almost 200 witnesses and saw over 300 exhibits. They included videos of Dwyer stabbing Ms O’Hara and two other women during separate sex acts, and stories he wrote in which he described himself, raping and killing women in graphic detail.
Crucial among the other exhibits were two phones and a laptop found in Ms O’Hara’s home following her disappearance; she had synced her iPhone with her laptop and some of her older text messages were sill available.
Other incriminating evidence included Dwyer’s DNA profile found in semen on her mattress a year later; the discovery of her remains and keys in separate counties led to the missing-persons investigation being upgraded.
Also vital to the prosecution were two mobile phones, glasses, and a backpack discovered with Ms O’Hara’s keys in the reservoir. They were found after the water level had dropped from 20ft to less than 2ft following the particularly warm summer of 2013. They were recovered in an intensive Garda search, after three local men noticed unusual items in the water while stopped on a bridge over the fishing spot.
The two anglers and their friend fished out a rope, handcuffs, leg restraints, bondage cuffs, a ball gag, a blindfold, a hoodie, and vest.
A garda later found sex toys, a knife, an inhaler, a set of keys, and a supermarket loyalty card in Ms O’Hara’s name. The keys were later found to be the keys to Ms O’Hara’s car and home, and glasses matched both her prescription and frames she had purchased.
A backpack found was connected to Dwyer: CCTV captured him leaving Ms O’Hara’s home with it just a week before her disappearance. The bag was never captured being returned to the building.
Specialist gardaí managed to extract data from Ms O’Hara’s two phones and laptop, as well as from the phones that had spent a year submerged deep under water.
Despite the two reservoir phones being unregistered, the State managed to convince the jury they had been purchased by Dwyer and used by him and Ms O’Hara. Each was the only phone number stored in the other’s handset and they were saved as MSTR and SLV; they were known throughout the trial as the Master and Slave phones.
The prosecution also proved another phone number with which the deceased had been communicating belonged to Dwyer. The handset for this number was never found.
However, it had been registered, albeit in a fake name. The content of the messages recovered showed Dwyer and Ms O’Hara had a sexual relationship, an unusual central feature of which involved the accused stabbing her. It was a BDSM-style relationship in which he was the dominant party and she the submissive. He called her Slave and she called him Master.
The prosecution said this and the content of the messages reflected “a deep-seated, passionately-held, irrepressible desire on the part of Graham Dwyer to get sexual gratification by stabbing”. The phone evidence satisfied the jury that Dwyer arranged to meet his victim at Shanganagh.
The texts told the story of their relationship but also revealed her killer’s identity.
One of the messages that led detectives to suspect Dwyer was a text sent in March 2011 in which he named the baby girl, who had just been born to him and his wife. Another crucial message mentioned his flying hobby and recent pay cut. “Terrible. 15% pay cut and came fifth in flying,” read the text about his weekend sent to Ms O’Hara in June 2011.
A trawl through the cell sites used by the phones led gardaí to examine toll records from roads across the country. They were looking for a car registered to a man living in south Dublin and working in Dublin 2. They found the Master phone moved around Ireland at the same time as Dwyer’s cars.
The jury heard two detectives confirmed their suspicions when they took items from the Dwyer family’s bins . They matched DNA from a container of turtle wax with the DNA from the semen on the victim’s punctured and bloodstained mattress.
He was arrested at his home on the morning of October 17, 2013, and gardaí searched both his house and his workplace on Baggot St where he was a partner in architecture firm A&D Wejchert.
What was found on electronic devices in his home shocked even the judge. Among the family videos and photographs, including baby scans, were numerous videos and photographs of women being stabbed and mutilated. There were also documents he had written about carrying out sex crimes and murder.
Dwyer denied killing Ms O’Hara during his Garda interviews. He eventually admitted being in a relationship with her but said it was Ms O’Hara and not him, who was interested in stabbing.
The videos and text messages told the truth, however. At the end of a video in which he stabbed Ms O’Hara during sex, he could be heard saying: “Now, that wasn’t bad, was it?”
Once the jury was satisfied the phones were Dwyer’s, it was in the content of the text messages where the main evidence against him lay.
The messages displayed a relationship between a controlling, dominant man and a vulnerable, submissive woman. Once she realised who was texting her, she informed him that she was no longer into blood and stabbing. He spent th e following year and a half trying to change her mind.
He also asked her if she was still suicidal in those early text messages. He frequently offered to end her life for her, but she said she wanted to live.
There were occasions when Dwyer seemed to get the message that she did not want to be stabbed and did not want to die. On those occasions, he told her she would have to help him find another woman to stab.
He identified an auctioneer, who worked across the street from his office, and outlined a detailed plan to kill her at a house she was showing. Ms O’Hara refused.
She tried to end the relationship at one stage, telling him she didn’t want to be his bit on the side anymore. She wanted a relationship and to have a child. He offered to father her child if she helped find someone for him to stab.
“A life for a life,” he said.
After her admittance to hospital, he told her in text messages he would punish her for trying to kill herself without him and for being unavailable to him for so long. He told her this punishment would come on the Wednesday night of her release. He told her it would be outdoors. He said he would stab her in the guts and that it would be like he was doing someone for real.
He also asked her if anyone knew about him. She assured him that nobody did. “That’s good. No one should know about me,” he wrote.
The last sent messages he sent her were directions to their meeting place. “Go down to shore and wait,” was the final text he sent her at 6pm. Neither phone was used again.
A dramatic afternoon of evidence had been provided by a young American woman, who had met the accused on the internet. Darci Day testified she had been suicidal and he offered her “a solution”. She said he had told her he wanted to kill Ms O’Hara if she wanted, and then go after Ms Day.
A document called Killing Darci found on his hard drive described her flying to Ireland, being met by Dwyer at the airport and being taken to a cabin.
There he described raping and stabbing her to death in graphic detail. He also described having sex with her corpse afterwards. This was one of the documents for which the public was excluded from court.
In another document, Jenny’s First Rape, he described travelling to Newcastle and abducting a young woman from a bookshop, taking her to his hotel at knife point and violently raping her.
He also described almost strangling her and then threatening her with a knife, at which point he said the fun was only beginning. This was the second piece of evidence for which the public was excluded from court. A third document described a woman being attacked and raped in a Dublin park.
The defence argued these documents were fantasy, but the jury did not agree.