Gardaí are trying to trace the movements of a van that was used in an attack at Bray Boxing Club in Co Wicklow this morning in which a 50-year-old man was killed.
He has been named as father-of-three Bobby Messett. He also had three grandchildren.
Mr Messett participated in charity kayaking and was a member of his local football club, Glencormac United, in Kilmacanogue near Bray.
It is understood he regularly attend circuit training classes at the gym in Bray Boxing Club.
Two other men, aged 35 and 57, were injured in the incident and were taken to hospital for treatment.
Boxing trainer Pete Taylor, the father of world and former Olympic champion Katie, was one of those injured.
Gardaí described their injuries as serious but not life-threatening.
A gunman entered the boxing club just before 7am and fired a number of shots.
It is believed he was wearing a high-visibility jacket and had his face covered.
The suspect fled the scene after the attack in a van.
A technical examination of the area is being carried out by crime scene examiners.
Gardaí are trying to trace the movements of a silver-coloured Volkswagen Caddy van with Northern Irish registration plates that was used in the shooting.
It is believed that the van travelled from Bray through Shankill and the Cornelscourt area before being abandoned on Pigeon House Road in Dublin at around 8.05am this morning.
A man was seen leaving the van and cycling away, gardaí said.
A motive for the shooting has not yet been established and gardaí said trying to find it would form a key part of the investigation.
Gardaí are appealing to anyone who witnessed the movements of the van along the route travelled between 7-8am this morning to contact them.
In particular, they would like to hear from anyone with 'Dash Cam' footage along this route.
They are also looking to hear from anyone who may have witnessed the man cycling away from Pigeon House Road at around 8.05am.
Anyone with information is asked to contact Bray Garda Station on 01-6665300, the Garda Confidential Line on 1800 666 111 or any garda station.
Minister for Justice Charlie Flanagan described news of the shooting as shocking.
Speaking on RTÉ's Morning Ireland, he appealed to anyone with information in relation to the incident to come forward.
Bray Boxing Club is where Katie Taylor trained during her amateur career.
It was set up by her father and is also home to other Olympic boxers, including former Irish champion Adam Nolan.