Gardai investigating the murder of pensioner Thomas Horan have appealed for taxi drivers who might have picked up a man and a woman close to his address to come forward.
In a renewed appeal, gardai say they are looking to speak to taxi drivers who picked up or dropped off two people close to Mr Horan's address.
They believe a taxi driver may have dropped the two people close to Cambridge Court, Ringsend between 2am and 5am on Monday morning of the 6th January 2014,
It's believed Mr Horan was beaten to death at his home in a complex for the elderly had allowed callers into his home.
Gardai believe the 63-year-old victim knew his killer, and invited his killer into his apartment after answering a knock at the front door.
Two suspects, a male and a female are currently being held at Irishtown and Donnybrook garda stations and can be detained without charge for up to 24 hours, excluding rest periods.
A post-mortem carried out yesterday by State Pathologist Professor Marie Cassidy confirmed that Mr Horan died from injuries he received during an assault.
Officers said they were satisfied that no weapons were used during the attack at the senior citizens' apartment block in Cambridge Court, off Cambridge Road, in Ringsend, south Dublin.
Last night, investigating gardai were questioning a 27-year-old man and a 37-year-old woman, who had been arrested on the northside of the capital yesterday afternoon.
Officers said they were satisfied they were making progress with their inquiries but appealed for help from the public.
Mr Horan, who was originally from Mullingar but had been living in Dublin for several decades, moved into the complex more than three years ago.
He was a separated father of one and his wife lives in a flat in another area of the south city.
The emergency services were alerted by a 999 call at 4am on Monday when neighbours became concerned after they heard shouting inside the apartment.
Mr Horan's fully clothed body was discovered in the bedroom of the ground-floor apartment. There were no visible marks on the body and he was pronounced dead.
The area was immediately sealed off for a detailed garda technical examination. Mr Horan's body was removed to the pathologist's office and a murder inquiry was launched after the post-mortem results became known.
There were no signs of a break-in at the apartment.
Mr Horan is the father of an adult daughter, who is believed to be living in the UK and had previously worked for several years with the Marist Fathers in Milltown, Dublin.
Gardai last night issued an appeal to anybody who saw or heard suspicious activity in the sheltered complex between 10pm on Sunday and 4am on Monday, to contact them at Irishtown station, on 01 6669600, or on the confidential line, 1800 666111.
Superintendent Dave Taylor said: "Thomas was a quiet man, very well-respected by his neighbours and he enjoyed his music.
"Cambridge Court is an old folks' home and approximately 40 people live there.
"This is a very quiet residential area. It's a place of safety and comfort for the elderly people up there.
"As you can imagine, they're quite shocked with an incident like this and quite disturbed."
By Tom Brady and Cormac McQuinn