The man who was stabbed to death in Dublin in the early hours of this morning has been named as 39-year-old Peter Donnelly who was from Kilkenny.
The stabbing happened on O'Connell Street at around 1.40am, after a row broke out between two men who had previously been talking to each other on the street.
One produced a knife and stabbed the other several times.
Mr Donnelly was taken to the Mater Hospital, but was pronounced dead there earlier this morning.
A uniformed garda had earlier seen the two men and asked that they be monitored on CCTV.
A 28-year-old man was arrested on nearby Marlborough Street 15 minutes later. A section of Marlborough Street outside the Pro-Cathedral was also sealed off.
The man was taken to Store Street Garda Station and detained under Section Four of the Criminal Justice Act.
However, his detention was subsequently suspended, so that he could be taken to hospital for treatment for cuts to his hands.
He remains in custody tonight.
Gardaí at Store Street have begun a murder investigation and a weapon has been recovered.
They are gathering CCTV footage and asking for witnesses or anyone who was on O'Connell Street between the Henry Street-Parnell Street junctions between 1.30am and 2am this morning to contact them.
Detectives are following a definite line of inquiry and are not looking for anyone else at present.
They suspect the killing could be the result of a row among homeless people in the city.
Gardaí have appealed to witnesses or anyone with information, or who may have mobile phone footage, to contact Store Street Garda Station on 01 6668000, the Garda Confidential Line on 1800 666 111 or any garda station.