The killing of an 18-month-old child was "bizarre in the extreme" but the guilt of the accused man depended on whether or not the act was voluntary, a murder trial jury heard yesterday.
Opening the defence case, Mr Patrick Marrinan SC said the accused man, Mr John Reilly, is "somebody who is not thought to be capable" of doing what he is accused of - murdering infant Oisín Reilly-Murphy.
The accused man did not accept that he killed Oisín, Mr Marrinan said, but the "stance he has taken" is that the evidence pointed to him.
Mr Marrinan told the jury that the entire nature of the trial was extremely unusual.
"What we are presented with is the irrational, the bizarre," he said. There was nothing to suggest a motive or reason "but maybe there is an explanation".
In evidence, expert medical witness Dr Catherine Crowe, a specialist in parasomnia and other sleep disorders, told the Central Criminal Court that episodes of marked confusion could occur in a parasomniac state known as confusional arousal.
Questioned by the defence, Dr Crowe said some 20 documented cases of homicides were attributed to confusional arousal, the features of which were disorientation and perceptual impairment.
She said that in her opinion, the accused met most of the criteria for confusional arousal. However, following objections from Mr Anthony Sammon SC, prosecuting, Mr Justice Carney said it appeared that the jury was being asked to speculate on a theory.
When asked about the possible effects of alcohol in relation to confusional arousal, the witness said a combination of factors must be taken into account.
One was "the excessive amount of alcohol" the accused had consumed. The other was that Mr Reilly had gone into a deep sleep at a very late hour.
"These two factors together contributed to a confusional state," Dr Crowe told the court. This combination would "significantly reduce his capacity to be aware of his acts," she added.
Mr John Reilly (32) of Crooksling, Brittas, Co Dublin has pleaded not guilty to the murder of Oisín Reilly-Murphy on June 5th, 2000 at Jobstown, Co Dublin.
The trial continues today .