It was earlier believed the elderly man died following a domestic dispute.
Gardaí in Ronanstown, County Dublin investigating the death of a 74-year-old man, discovered at a house in Rowlagh Green on July 13 have arrested a 47-year-old male.
He was arrested July 14 in Lucan, County Dublin and is being detained at Lucan Garda station under the provisions of section 4 of Criminal Justice Act 1984 as amended.
At approximately 8.45pm on July 13, Gardaí in Ronanstown were called to a house at Rowlagh Green, Clondalkin where a male had been injured.
On arrival, a 74-year-old male was discovered with serious injuries.
It is believed that there was an earlier domestic dispute at the house.
The injured male was taken to Tallaght Hospital and later pronounced dead.
A post-mortem is scheduled to be carried out on July 15 by the State Pathologists Office at the City Mortuary.
Gardai wish to appeal to witnesses or to anyone who can assist with the investigation to contact the Incident Room at Ronanstown Garda Station on 01 6667700, The Garda Confidential Telephone Line 1800 666 111 or any Garda Station.