The journalist was shot six times in her car on June 26, 1996, while she was stopped at traffic lights. She was the mother of a six-year-old boy. 

John Gilligan had previously beaten her up and threatened to kill her and rape her son. 

Following the murder, additional Garda resources, new legislation, establishing a witness protection programme, the Criminal Assets Bureau, as well as using the Special Criminal Court for gangland criminals, were provided by the State. 

The investigation led to the gang being dismantled, with key members imprisoned for lengthy periods. 

Her brother, Jimmy Guerin, told RTÉ News an apology would help the family, in some small way, before the Parole Board decides to release Brian Meehan, who was convicted of her murder.

Mr Guerin said: "We are dealing with immoral individuals 

"I find that very hurtful to be honest, and then I see Meehan in front of the Parole Board, and I would think the least they should look for is for him to acknowledge his role in the murder of Veronica," he said. 

"And would that make a difference? It would make a small difference because, by acknowledging it, at least he is admitting his wrongdoing, and we would feel a little bit better, if that makes sense. 

"I think an acknowledgement would be useful to the family, and I think it would be useful to a lot of people. A lot of people put their heart and soul into trying to solve this investigation. 

"And they successfully did it in my view. Yes, they dismantled the gang, yes, they broke up what could have been a huge criminal empire, but unfortunately, these are replaced. 

"So, yes, I think an apology would make a difference," Mr Guerin added. 

Ms Guerin will be remembered on Friday at a community walk to the place where she was killed. A fundraising event for St Francis Hospice will also be held at the Convention Centre, which will be attended by the Taoiseach, senior Government and opposition figures, the Garda Commissioner and a large number of public representatives.