The man who has been stabbed to death and his body wrapped in a plastic bag before it was dumped in a wardrobe has been named locally as Christopher Jackson.
Two men and a woman are being questioned over the murder of the 53-year-old.
The grim discovery was made by gardaí after a tip-off to go to the property on Prussia Street in Stoneybatter in Dublin’s north inner city on Saturday afternoon.
A Garda source said the body may have been there for a number of days.
It was concealed and stuffed in the bottom of a wardrobe and the killer had planned to move it before gardaí moved in, he added.
Detectives are investigating a motive for the knife attack, believed to have centred on a row over money.
Joe Costello TD, who lives a street away from the murder scene, said the local community is shocked.
“It’s a terrible tragedy to have happened anywhere,” said the Minister of State.
“You do not expect it in your own neighbourhood.
“It’s a very settled area with a lot of elderly people here as well as young professionals moving in..
“It was a total shock to people at Mass.”
Mr Jackson had lived at the property with his partner and son.
The scene was cordoned off shortly before 3pm on Saturday and the case upgraded to murder after assistant State pathologist, Dr Michael Curtis, examined the scene and confirmed the body was a man.
A post mortem is expected to determine the exact cause of death.
A man aged in his 30s and a woman in her 40s, who both knew the victim, were later arrested in the city centre and questioned in the Bridewell and Store Street Garda Stations.
A second man, also aged in his 30s, was detained earlier today and taken to Mountjoy garda station.
Elsewhere, gardaí in west Cork are waiting to resume questioning a man in his 70s in connection with a suspicious death.
The victim, a 53-year-old man from England, was discovered at the bottom of an embankment in the Seskin area of Bantry on Friday evening.
It is believed he suffered injuries during an assault before his death.
A suspect in his 70s was arrested but was rushed to hospital when he felt unwell.
He remains under arrest.