A man in his early twenties died last night after becoming ill at a concert in Dublin's Phoenix Park in which seven people were also stabbed.
The man was attending the Swedish House Mafia concert in Dublin.
He was treated by medical staff at the site before being taken to Blanchardstown Hospital where he was pronounced dead.
Gardai have not been able to identify the man and are asking family and friends to check that loved ones have arrived home safely from the event.
Anyone who has concerns regarding a friend or relative should contact Blanchardstown Garda Station on 01 666 7000.
Separately, a man has been arrested after a number of stabbing incidents at the same concert.
All told, seven men were wounded and brought to hospitals around the city for treatment.
All but one of the men were subsequently discharged. One man is still being treated at Connolly Memorial Hospital in Blanchardstown.
A 23 year old man at the scene and he is being questioned at Blachardstown Garda Station, under section 4 of the Criminal Justice Act.