The first spectators arrived well before 9am, laden with cushions and sandwiches. It would be 3½ hours before the first witness appeared, but doubtless the onlookers regarded it as time well spent.
At about 12.30pm, through a sweaty, airless, intensely curious court, an apprehensive-looking Nikki Pelley, the 37-year-old woman with whom Joe O'Reilly had admitted to an affair, made her way towards the stand.
As she passed within inches of O'Reilly, he was the only person in court not to follow her progress. He continued his businesslike jottings while the woman addressed as "my beautiful bride to be" in a text from his phone to hers three weeks before Rachel's death, took the stand.
Wearing a gold band on her wedding finger and dressed in a white linen tunic and long, gypsy-style, red skirt, she took the first of many sips from a glass of water.
Under the brusque questioning of State prosecutor Denis Vaughan Buckley, intimate details of an adulterous affair, the kind that no couple would ever wish to see the light of day, slowly emerged.
How they met at a business function in the Barge pub in Portobello, how they kept in touch by e-mailed jokes and texts, how it progressed to lunches in the Templeogue Inn a couple of months later, then to the cinema in Liffey Valley a few weeks later. How it moved to a sexual relationship pursued three or four times a week in her Rathfarnham home, on Saturday afternoons and overnight after softball games on Tuesdays and Saturdays, when he told his wife he was staying on a camp bed in the office.
At the back of the court, O'Reilly's mother Ann, accompanied for the first time by her younger son, Derek, stared impassively ahead.
The Callaly siblings and spouses held hands and placed a protective shield around their mother and father, all eight of them squashed into a single bench. Rose Callaly flinched when Ms Pelley said she had met Joe and Rachel's two sons, who knew her as "Nikki", and who had spent Saturday afternoons with them at her home and at the zoo. They flinched again when a text from his phone to hers on August 31st referred to "our boy" - "Our boy has just had his first school day. He had lots of fun but will have lots of homework tomorrow. Love you xxx."
Rose gripped her husband's hand while she heard how Ms Pelley had once stayed at the O'Reilly marital home in the Naul while Rachel was away and how after Joe O'Reilly's appearance on the Late Late Show with Rose Callaly to appeal for help to find Rachel's killer, he spent the night with Ms Pelley.
The c**t word, used twice to describe his wife in Joe O'Reilly's e-mails four months before her death, arose again when Nikki Pelley was asked how he would refer to Rachel after an argument. " 'Wasp' would be one of the words". Any others ? "C**t" . It wasn't a term he used often, she added.
As the day drew to a close, messages left on the O'Reillys' landline and Rachel's mobile , included four voicemails and a text from her husband. "I've been crying - you have me worried. Talk to me," read one.
