The Cork-born father of three was last month found guilty of murdering the 36-year-old Dubliner by stabbing her for his sexual gratification in the Dublin Mountains.
The former architect had been on trial at the Central Criminal Court for more than two months, charged with her murder on August 22, 2012, hours after she was discharged from a mental health hospital.
The 42-year-old, of Kerrymout Close, Foxrock, Dublin had pleaded not guilty to her murder at Killakee, Rathfarnham.
However, a jury of five women and seven men was satisfied that he lured her up the mountain that evening to stab her in pursuit of sexual gratification before disposing of her belongings to make it look like suicide.
Some 11 members of the jury returned to court yesterday to see Dwyer given the mandatory life sentence for his crime.
Mr Justice Tony Hunt told them their presence demonstrated that they were responsible people, anxious to see the very end of the process.
He thanked them for accepting the invitation, telling them it was not a usual feature of the process.
“But, then so little about this case can be described as usual,” he said in a courtroom packed to capacity.
He said it had been a very harrowing trial involving a number of families, including Mr Dwyer’s family, who he described as “blameless”.
In imposing the mandatory life sentence on Dwyer, Mr Justice Hunt said it was a sentence “he richly deserves”.
“It’s difficult to look beyond the chilling and premeditated murder, execution almost, carried out after a protracted campaign of the most vile manipulation and abuse of a woman too weak to resist, and who made the fatal mistake of trusting Mr Dwyer and that he wasn’t going to go any further than he indicated,” said Mr Justice Hunt. “That’s the tragedy.”
He said that one could read the booklet of text messages sent between them and cry out for her to stop and turn back.
“Of course, it’s much too late for that,” he said. “So that’s it. Life it is.”
He granted a defence request for a legal aid certificate in the event of an appeal.
Dwyer was then led away to begin serving his life sentence.
Ms O’Hara’s family left without addressing the large numbers of media present.