A "quiet" teenager who stabbed his mother's violent ex-boyfriend to death during a row at the family home has been sentenced to two years in prison.
Alexander Whelan (19) introduced a deadly weapon into the row and used substantial force in inflicting the wounds that killed Bruno Rolandi, Mr Justice Michael White said at the Central Criminal Court.
Whelan was originally charged with murdering Mr Rolandi (56) on November 19, 2017.
But Whelan pleaded guilty when a charge of manslaughter was put to him at the court in November last year.
The two greatest aggravating factors in the case, Mr Justice White said, were the introduction of the knife and the violence of the blows. He said a pathologist's evidence showed substantial force was used, including one knife wound that went to a depth of 23 centimetres, damaged the heart and caused massive bleeding, leading to his death.
He said the defence case was that Whelan was acting in defence of his mother and brother, but used excessive force.
There was also evidence Whelan was provoked by the actions of Mr Rolandi.
He said there was a "dysfunctional relationship" between Mr Rolandi and Whelan's mother.
The relationship, he said, had come to an end and they were living separate lives, but Mr Rolandi remained an "unwelcome guest" in the Whelan home at Green Road, Ballymoran, Edenderry, Co Offaly.
He noted Mr Rolandi had issues with alcohol and heroin and "created a tense situation in the family home".
On the day of the stabbing there was an argument between Ms Whelan and Mr Rolandi and Whelan intervened but was sent away.
He called his brother Victor and they discussed removing Mr Rolandi from the house.
Mr Rolandi came into the kitchen and there was a dispute between Victor and Mr Rolandi.
Alexander Whelan, thinking his brother was being attacked, inflicted the fatal wounds, Mr Justice White said.
He said Whelan was of previous "excellent character" and had an excellent record at school. He was not, he said, disposed to violence. He added: "He is a quiet young boy, not in any way aggressive."
The judge also noted Whelan - of Green Road, Lumville, Edenderry - had apologised profusely to the family.
However, he also noted Mr Rolandi had "received a death sentence which was entirely unnecessary".
He set a headline sentence of six years' imprisonment but said he would discount that and impose a sentence of two years.
He did not see any point in suspending any part of the sentence as Whelan was not a drug user and did not require rehabilitation as he had no history of violence.
Whelan's mother broke down in tears as he was led away.