So when neighbours in the cul-de-sac at the end of Galway’s Lane heard a man twice roar “open the fuckin’ door” in the early hours of Monday, followed seconds later by the sound of a door slamming, they didn’t think much more about it.
But waking to the news yesterday that Mr O’Callaghan had been found dead, lying in a pool of blood having suffered extensive head injuries, has left the tight-knit community shocked and devastated.
Many of the older residents have now expressed fears for their safety and have called for out-of-action porch lights to be repaired.
Mr O’Callaghan, 66, a father of three grown-up children and originally from the Grange area of the city, was found fatally injured by his wife, Angie, at the house yesterday.
Originally from Bulawayo, in Zimbabwe, Angie arrived home at around 8am after night-shift work and saw a panel at the bottom of their front door had been kicked in.
She raised the alarm minutes later when she discovered the body.
She was being comforted by members of the community yesterday.
The couple married about a decade ago — Mr O’Callaghan’s second marriage — and they had lived on Galway’s Lane for about five years.
Neighbours said that Mr O’Callaghan had “his difficulties in life” but, despite those and various health challenges, he had been feeling better and happier in recent months. He had recently become a great-grandfather.
His sister, Sheila Thornhill, who visited the scene with some of her brothers, said she last saw Mr O’Callaghan on Saturday.
“I hadn’t seen him as good in a long time,” she said. “He lived there for the last five years. He would come and go as he pleased. He felt safe there.
“Just find whoever did it to him.”
She said her family was struggling to come to terms with the circumstances of his violent death.
The scene was sealed off and detectives were working yesterday to establish Mr O’Callaghan’s last known movements as they officially classed the circumstances of his death as “suspicious”.
The results of an autopsy to be conducted by assistant state pathologist Margot Bolster at Cork University Hospital this morning will determine the course of the investigation. However, gardaí are expected to upgrade their investigation.
They are exploring a number of avenues of inquiry, including the reports of the violent altercation on the doorstep several hours later. They are also investigating reports from two neighbours who said they saw a man in his 20s with dark hair walking away from Mr O’Callaghan’s house around 9.30pm on Sunday.
It is not clear if this man is linked to the violent row several hours later.
One neighbour said they could not provide a more detailed description of the man because lights in the estate had been out of action for almost a year, despite repeated requests to Cork County Council and the ESB to have them repaired.
As forensic experts combed the house for evidence and as a Garda sniffer dog searched ditches which run between the housing development and Douglas GAA club, neighbours spoke of their concerns.
One man said Mr O’Callaghan associated with people from “all walks of life” and that they had to complain on several occasions about loud parties at the house, which were attended by “all sorts of characters”.
Another neighbour, John O’Sullivan, who went to school with Mr O’Callaghan, said Angie called to him for help at 8am yesterday.
"I had heard the noise the night before but didn’t really pay attention,” he said.
He and his neighbours are now living in fear, he said.
It’s a tight-knit community and this is scary — you think this doesn’t happen here, it’s for older people,” he said. “I’m shocked. I’ll be shocked for a while. It’s something you don’t expect in a place like this.
“It’s quiet. We’re all over 60, and you don’t expect people to come up here.
“You feel safe but, yet, we’ve been ringing the council and the ESB about the lights for the last 12 months. The lights are all broken and it’s pitch dark all night.”
Local county councillor Joe Harris, who also went to school with Mr O’Callaghan and who met him last week, said he was a valued member of the local community and deserves justice.
“I knew Joe very well,” he said. “We’d have coffee in Tesco regularly. He was a bit of a character, always laughing and joking.”
However, Mr Harris said Mr O’Callaghan never mentioned any concerns he had about security.
He was a happy-go-lucky fella,” he said. “He was a very easy-going fella.
“I’m just gutted. I can’t believe it. It’s a tragedy.”
Clement Collins, who said that he knows one of Mr O’Callaghan’s neighbours, said it felt surreal to see crime scene tape in the neighbourhood.
He said gardaí have had to deal with an increase in alcohol-related antisocial behaviour in the area — but nothing like this.
It seems surreal in a way because you’d usually see this on TV and now, this is the real thing. It’s like a dream,” said Mr Collins.
“It’s a bit worrying because I live on my own. I don’t know what happened here and that bothers me. The impression I get from the amount of violence on the streets is that life is cheap. At least today.
“It would make you feel cold and shocked really. A friend of mine lives up here and when this happens, the worst could come into your head and you’d think it could be the person you know.”