Mr Tormey (49) had been at a party on Saturday night and into yesterday morning and got home to his house on Thomond Road at around 3.30am.
He was shot in the front garden of his house just over an hour later at 4.35am while his wife and one of his children were asleep inside, according to gardaí.
Independent.ie has learned that he was shot three times in the chest with a handgun.
At a press briefing at Ballyfermot garda station Supt Tony Twomey said the investigation was at an early stage and he appealed for any witnesses or anyone with information to come forward.
He said Mr Tormey was not known to be involved in any criminality. As such, a motive for his murder is not fully clear.
“At 4.35am on Sunday, Michael Tormey was fatally wounded in a callous attack at his home at Thomond Road, Ballyfermot. This attack occurred while his wife and child were asleep in the house. Today I'm appealing for any persons who may have been in the area of Thomond Road and Kylemore Road from 3.30am on Sunday morning, and who may have witnessed any unusual activity, or persons who may have dash cam or CCTV footage, to contact Ballyfermot Garda station on 01 16667200, or the guard confidential line 1800 666111,” he told reporters.
“I'm aware of the concerns in the Ballyfermot community, and I want to reassure that the necessary policing response through investigation and proactive policing will be provided to allay their concerns.
“We’re at the early stages of our inquiry but we have nothing at this stage to suggest that it's linked to any earlier events. We are aware that he was at an event earlier, but we're satisfied at this stage that there is no connection to that event.”
“We were satisfied at this stage that Mr Tormey had no links to criminality that we're aware of at this point in time, and we're satisfied that events that were attended earlier are not linked to this incident,” he added.
Supt Twomey said door-to-door inquiries were being carried out as is usual in these investigations.
“We are pursuing a number of lines of investigation and we're following up with witnesses at this time. We have a full investigation team assigned to this,” said Supt Twomey.
There are approximately 20 officers working on the case.
Senior sources earlier said a major line in the case had been whether Mr Tormey had been involved in a disagreement with local criminals who were asked to leave a house party just hours before he was shot dead in the front garden of his home.
It was being investigated whether the gunman or gunmen then arrived at the victim’s property on Thomond Road and fatally shot the victim as he stood in the garden.
But gardaí have ruled this out.
The wife and six-year-old daughter of Mr Tormey were asleep in the house at the time he was killed.
Gardaí were today continuing a forensic search of the garden and neighbouring gardens.
Nobody heard the shots despite Mr Tormey being hit a number of times.
The father of two was later found slumped on the driveway between the front door and a car, and a call was made to Dublin Fire Brigade who then alerted gardaí after they attended the scene.
Family friend and local councillor Hazel de Nortúin told RTÉ Radio One’s Morning Ireland that Mr Tormey was a hardworking man who lived for his family.
He was into fitness and training and enjoyed singing karaoke with his friends.
“He was good friends with my husband, he was only at our wedding in August and he was a very decent, hard working man, he was a loyal friend and his sole focus and purpose in life was working with his children and his family to make sure they had everything they need,” she said.
“He would have been a private man in ways, focused on his fitness and his training, and he enjoyed partaking in the karaoke scene that would be famous around these parts of Ballyfermot.
“All round a very joyous, nice, loving man and it's a huge loss to our community, it’s unbelievable that this has happened, It is very shocking to process it all.
“He spoke so highly of his life constantly and the children, he was a genuinely really nice man.”
Independent.ie last night, Ms de Nortúin said: “He was a very decent man, a family-orientated man and he was a great friend to those who knew him.
“I never heard a bad word about him from the time I knew him. This is a tragedy.
“He only got married in 2019 and my condolences go to his wife and children. The community is completely shocked.
“I really want to extend my condolences to those who knew him and the community of Ballyfermot,” she added.
More to follow…