A mother whose son was killed by a man who was out on bail says he would still be alive if the gardaí had done their basic duty.

Shane O'Farrell had come home to take part in a triathlon in August 2011, and went out for a ride on his bike.

When he did not come return, his parents went out looking for him. They found he had been killed in a hit and run incident.

It later transpired the man involved, Zigimantas Gridziuska, was a drug addict with more than 40 previous convictions.

He was at large because of two suspended sentences imposed by courts on both sides of the border.

The Lithuanian man was stopped and searched by a drug squad detective, in a car that had no tax and was later found to be unroadworthy - but was waved on.

One hour later on the outskirts of Carrickmacross, Co Monaghan he ran down down 23-year-old Shane O'Farrell.

"They had numerous opportunities to stop him, it wasn't one", Lucia O'Farrell told the Pat Kenny Show here on Newstalk.

"We do know that seven months prior to him killing Shane the court - in Monaghan Circuit Court - ordered that he be returned to court if he re-offended".

"We do know the gardaí failed to put that on the Pulse system - he did re-offend four months later and he should have been returned to court".

"So on the evening in question, he should not have been at liberty to kill".

"Had the guards done their basic duty he would not - he would have been in custody" she added.

Here her full interview below: