A JURY has begun deliberating in the trial of a 32-year-old man with schizophrenia, charged with murdering his mother at their home last year.
Niall Stapleton of Glebe Lodge, Kilfane, Thomastown, Co Kilkenny denies murdering Siobhan Stapleton (51) at that address on May 25, 2012.
She died from blunt force trauma to the head after being beaten with the handle of a garden implement.
The Central Criminal Court heard that the college graduate maintained he was not guilty by reason of insanity. He told doctors he thought his mother had been replaced by an impostor when he killed her.
An expert witness for the prosecution testified yesterday that Mr Stapleton met the requirement for the special verdict of not guilty of murder by reason of insanity.
The clinical director of the Central Mental Hospital, Professor Henry Kennedy, said that at the moment he was striking his mother, the accused believed he was striking a doppelganger.
"The necessity of dealing with this double meant he was unable to refrain from the act. He didn't see another option," he said.
During an interview, the accused had told Prof Kennedy that voices began telling him that his friends didn't exist. He wondered who he had been hanging around with if they didn't exist.
He said he then saw the silhouette of his mother in the garage and thought that something dark had shifted into her.
"I thought it wasn't my mother, that something had replaced her," the accused had told Prof Kennedy. "I picked up the spade. I thought I'd better deal with this." He then said his mother came outside.
"I swung out and hit her on the head two or three times and she fell on the ground. I came round then and said: 'Oh God, what have I done?' and ran and put the spade handle on the grass," he continued.
"It dawned on me what I'd done, that this wasn't a doppelganger. It was for real."
The jury must then decide if the accused was suffering from a mental disorder when he killed his mother.
They must then decide if such a disorder meant he did not know the nature and quality of his action, that what he was doing was wrong or that he was unable to refrain from the act.
If Mr Stapleton satisfies any of these three criteria they must find him not guilty of murder by reason of insanity
Mr Justice Garret Sheehan told them they had had two other verdicts open to them, guilty of murder or guilty of manslaughter if the prosecution failed to prove intent.
The case continues.