A man in his late 60s has died on Baggot Street Lower in Dublin city centre.
Gardaí said they were alerted shortly before 11pm last night “following reports of an altercation involving two males”.
One of them became unwell and was taken to hospital where he was pronounced dead.
A post-mortem examination is to be carried out, gardaí added, and the outcome of the examination will determine the course of the investigation.
Gardaí at Pearse Street are appealing to witnesses, including those with camera footage, to contact them on 6669000, the Garda Confidential Line on 1800 666 111, or any garda station.