A man has been killed and another critically injured after a row at a Christmas party in a house in south Dublin escalated into a knife attack that spilled onto the street in the early hours of this morning.

The dead man has been named locally as David Spain, who was in his late 20s. He has been confirmed to be from the same street in the Shankill area on which the attack took place.

He had been living in Australia and had returned home for the holiday period when he was stabbed.

The injured man is not being named by The Irish Times at this time.

Gardaí were alerted to the incident at Rathsallagh Park, Shankill, at around 5.30am today. When they arrived on the scene they found a number of people outside a house, two of whom were injured on the ground having suffered stab wounds.

Paramedics treated both men at the scene before they were taken by ambulance to St Vincent’s Hospital, south Dublin.

However, despite efforts by medical staff to save both men one of the victims was pronounced dead at the hospital around 8am.

The other man remains in hospital where his condition is described as critical.

The attack was witnessed by a number of people who had gathered at the house late on Christmas night and continued the party into the early hours of this morning.

Based on information supplied by some of those witnesses, gardai commenced their investigations on a definite line of inquiry.

One man in his thirties was arrested in west Dublin this morning.

He was detained under Section 4 of the Criminal Justice Act, allowing for his detention for up to 24 hours without charge. He is being questioned about the attack at Shankill Garda station where the investigation is based.

Gardaí believe the man who carried out the stabbing was known to the two injured men.

They are working on the theory that there had been a long-standing dispute between this man and the two friends who were stabbed.

Gardaí believe the man who carried out the stabbing had been at the house in Rathsallagh Park for some time before the other two men arrived.

The altercation began shortly after the arrival of those two men who were subsequently stabbed.

Gardaí have appealed to anyone who was at the party when the stabbing occurred, or local people who may have come out onto the street to investigate what was going on to come forward and speak to them in confidence.

The scene of the incident is in a residential area and gardaí believe a large number of local people may have seen or heard the attack or its aftermath.

The house where the attack began and the street outside where the two injured men were found were both sealed off immediately gardaí arrived at the scene.

The house and street were today undergoing a forensic examination by members of the Garda Technical Bureau.

The street outside the property, a nearby green area and gardens of neighbouring houses were also being searched by a team of gardaí in an effort to find any weapons that may have been discarded.

The State Pathologist’s Office has also been notified about the death. When the results of a postmortem on the dead man’s remains become available, it is expect gardaí will upgrade their probe from a suspicious death inquiry to a murder investigation.

Garda sources said all of the resources of a murder inquiry were already being applied to the investigation of the killing.

Anyone who was at the party or may have seen anything on the street outside is asked to contact Shankill Garda station on (01) 6665900.