Sources say officers have identified and interviewed the two young men who they believe brutally attacked Ciaran O'Connell at a house near Mullagh, Co Cavan.
"Gardai will be in a position to make arrests in the very near future. This is a murder investigation -- a definite line of enquiry is being followed," said a source.
The suspects are from Kells, Co Meath, and the Mullagh area. Both men were known to Mr O'Connell.
He was beaten and kicked in the head in front of his devastated girlfriend Emma Brogan during the attack at around 4am on Sunday.
The investigation is being led by Superintendent Gerry O'Brien who said yesterday: "Ciaran was in the foetal position on the ground when he got a bad beating.
"All the people who attended the house party have attended the station and have been questioned."
Funeral arrangements have not yet been finalised but Mr O' Connell is expected to be buried next week as his body remains at the morgue in Marino, north Dublin, today after a post mortem was carried out yesterday.
Preliminary results confirmed Mr O'Connell died as a result of blunt force trauma to the head.
He was taken to Cavan General Hospital at 4.40am on Sunday and was later moved to Beaumont where he passed away yesterday morning.
It has emerged that the victim -- who was originally from Dublin -- had clung to life for over 48 hours which enabled his sister Sinead to fly home from Australia to be at his bedside when his life support machine was switched off yesterday.
Ciaran's distraught girlfriend Emma posted on her Facebook page: 'Rest in peace babe xxxx.'