Updated 16.40:

The trial of a Dublin man accused of murdering his stepson has heard he fled the scene and did nothing to try and help him.

The prosecution believes David Mahon of Ongar Village in Clonsilla murdered Dean Fitzpatrick after confronting him for interfering with his bicycle.

Newstalk's Courts Correspondent Frank Greaney reports that David Mahon parked his bike outside a gym on May 24th 2013, and noticed a part was missing when he returned to it.

Dean Fitzpatrick called to his apartment the following night, and Mr. Mahon confronted him about it.

The 23-year-old admitted taking it to annoy him. The court heard Mr. Mahon wasn’t in a good mood and had been drinking that day.

It is the State’s case that when Dean left, Mr. Mahon followed him and stabbed him in the stomach with a large kitchen knife before fleeing the scene.

The jurors heard he told Gardai that he took the knife off Dean and claimed the young father ran at him and impaled himself on it. He said he thought Dean might have been suicidal.

The court heard Dean’s sister is Amy Fitzpatrick who hasn’t been seen since she went missing in Spain in 2008 – four years after they moved over there with their mother Audrey and the accused.

Her now husband denies the charge.