A 21-year-old was today jailed for six years for the manslaughter of his teenage sister.
Patrick O'Dwyer, of Shrohill, Ennistymon, Co Clare, became the first person in the state to be convicted of a killing on the grounds of diminished responsibility.
The apprentice butcher battered his sister over the head with a hammer and stabbed her 90 times while their parents holidayed in Gran Canaria.
In a victim impact statement Patrick's mother Clare O'Dwyer said life as the family knew it ended suddenly and tragically when God took their youngest child back home.
"Not only that, he let her die at the hands of her brother, our poor unfortunate son, Patrick," she said.
"Pa had no control over the events that happened that night, but he has to spend the rest of his life knowing that he killed his sister.
"Mags was too young to die."
This is the first time since the introduction of the Criminal Law (Insanity) Act 2006 that a person accused of murder has proved their responsibility for the killing was substantially diminished due to a mental disorder.
Defence psychiatrists told Dublin Central Criminal Court that the accused suffered from a mental disorder called 'depersonalisation disorder.'
His lawyer Patrick Gageby, SC, said he client seemed removed during interviews, as if he was a witness to the event.
Experts said he was blunt, distant and removed in custody, until he was given medication prescribed for epilepsy which changed his emotional tone.
The court heard the siblings were watching television together when Patrick went into the kitchen and picked up a hammer and hit her five or six times on the head.
The accused then went into the kitchen, picked up scissors and a knife, and stabbed his sister 90 times in the neck, trunk and legs.
He handed himself in to gardai the following day.
Mrs O'Dwyer said her daughter was a bright intelligent young girl, who had great plans for the future, adding that Patrick and Marguerite were like like peas in a pod.
"It is so unfair that her time on earth was so short," she continued.
"We have all been given a heavy cross to carry, but our son, Patrick, has been given the heaviest one of all.
"He will always have to live with the fact that he killed her."
Sentencing Patrick, Mr Justice Paul Carney lashed out at the Director of Public Prosecutions for not offering the court sentencing guidelines on the new law.
The judge said diminished responsibility reduces responsibility but does not extinguish it, adding he must take a significant amount of responsibility for the killing.
Backdating the jail term to November 30, 2004, he granted leave to appeal the sentence.