The family of Dean Fitzpatrick, 23, who was stabbed to death at the weekend say that they are totally shattered by his killing.
Dean's father Christopher Fitzpatrick told RTÉ News that he just wants the matter brought to a conclusion.
He has appealed for anyone with information to give it to the gardaÍ.
A 42-year-old man arrested and questioned in connection with the stabbing was released without charge
A file is being prepared for the Director of Public Prosecutions.
Mr Fitzpatrick, lost his only daughter Amy five years ago.
Dean was with him earlier that day as he was attending his younger brother's communion.
Mr Fitzpatrick described his son as a man full of energy with lots of interests and he said he just wanted matters in relation to his son's killing brought to a conclusion.
Amy Fitzpatrick went missing in Spain five years ago. She was just 15-years-old. She has not been seen since.
Dean and Amy's mother Audrey was too upset to speak today.
Mr Fitzpatrick said Dean found Amy's disappearance very difficult to deal with.
Dean's aunt Christine said Dean could not really talk about his younger sister.
Gardaí have recovered a knife as part of this investigation.
It is now being forensically examined to determine if it is the murder weapon.
A file on the case is being prepared for the Director of Public Prosecutions who will decide if criminal charges are to be prepared against the man released earlier.