A jury has heard that David Mahon told Gardai he "panicked" and didn't realise the seriousness of what happened during a fight with his stepson.
The 45-year-old, who denies murdering Dean Fitzpatrick, claims he ran into a knife he had taken off him at his apartment at Northern Cross in north Dublin.
Dean FitzPatrick, a 23-year-old father of one, called over to Dave’s apartment on the night of May 25 2013.
The court heard they argued and Mr. Mahon told Gardai that Dean grabbed a knife from the kitchen and started waving at him. He said he took it from him, and later confronted him with it on the landing outside his apartment.
He said he showed it to him and asked why he would pull a knife on his father.
He claims Dean then just came at him and while he saw some blood on the knife afterwards, he didn't think it was serious. He said he would have called an ambulance if he did.
Instead he “panicked” and left the apartment with a friend. He said he threw the knife out a car window as they drove around north Dublin.
He told Gardai that Dean would self-harm while they were in Spain and seemed to enjoy it, and he thought maybe he wanted to run on the knife.
The trial continues.