A taxi driver who picked three young men up after the Swedish House Mafia concert in the Phoenix Park in Dublin last summer is being asked to come forward to help gardai with their inquiries.
One of the passengers - a 21 year old - died at James Connolly Hospital on the night of July 7 after becoming ill a short time earlier.
The deceased and his two friends had hailed a taxi on the Navan road near the Ashtown gate between 11.30pm and 1.30am.
The taxi brought them to the Rosse Court area of Lucan - whereupon the deceased complained of being ill.
An ambulance was called and he was taken to hospital where he died.
The taxi driver is being asked to contact gardaí at Blanchardstown.