A Dublin man has gone on trial accused of stabbing his wife’s son to death following a row over his bicycle.

David Mahon of Ongar Village in Clonsilla denies murdering 23-year-old Dean Fitzpatrick in May 2013.

Dean is a brother of Amy Fitzpatrick, who has been missing since 2008 – four years after they moved to Spain with Mr Mahon and their mother.

It is the prosecution’s case that a row broke out after Dean took a part of his bike from outside a gym in Santry in Dublin.

Mr Mahon is accused of stabbing him in the stomach outside his apartment with a kitchen knife, a claim which the 44-year-old denies.

The court heard that he told gardaí that Dean Fitzpatrick was suicidal and ran into the blade.