It's believed Katie Taylor's dad was the intended target of a shooting at his boxing club in Bray.
A 50-year-old man was killed, while Pete Taylor and another man were left with serious, but not life-threatening, injuries.
A van believed to have been used in the attack has been found on Pigeon House Road in Ringsend.
The Irish Athletic Boxing Association says it is "horrified" at this morning's shooting.
It says its thoughts are with all those affected by what it calls an "appalling event".
Gardaí are now hunting for the gunman who they believe escaped in a silver coloured Volkswagon Caddy with Northern Ireland registration plates.
They are also examining CCTV, carrying out door-t-door inquiries and are appealing for anyone with information to come forward.
