Semen samples:Mr Justice Paul Carney's warning on the making of victim impact statements stems from Majella Holohan's digression from her statement that had been originally agreed by prosecution and defence at the sentencing of Wayne Donoghue.
Ms Holohan had submitted an 11-page statement before the sentence hearing at the Central Criminal Court sitting in Ennis, Co Clare, on January 24th, 2006, when O'Donoghue was scheduled to be sentenced for the manslaughter of her son, Robert.
However, after reading from the prepared script for 25 minutes, Ms Holohan caught everyone by surprise. After stating that doctors had urged her family to get on with their lives, she asked, "How can we, knowing there was semen found on my son's body?"
The issue of the semen arose during the investigation into the killing of Robert, whose body was found on January 12th, 2005, in undergrowth near Inch Strand, 11 miles from his home at Ballyedmond, Midleton, where he disappeared on January 4th.
The postmortem conducted by State Pathologist Dr Marie Cassidy revealed a trace of semen on a swab taken from the boy's closed right palm. This, along with other samples from Robert's body, was sent by gardaí to Britain for analysis.
A team under Dr Jonathan Whitaker at the Forensic Science Service laboratory at Wetherby examined the sample using a new DNA-testing technique called low copy number (LCN), which allows matches to be found from very few sample cells. Dr Whitaker, who pioneered the technique, tested the swab and compared it with a DNA sample taken from O'Donoghue when he was arrested on January 16th.
He concluded the likelihood of the semen sample coming from anyone but O'Donoghue was one in 70 million. On foot of his report in the spring of 2005, the DPP directed that O'Donoghue be charged with Robert's murder.
However, gardaí had also taken a number of items from O'Donoghue's house at Ballyedmond, Midleton, including a bathroom mat where he said he had put Robert as he tried to revive him after strangling him outside the house on January 4th.
Samples from this mat were sent to Wetherby, where Dr Whitaker again carried out DNA LCN testing. He concluded it also contained semen that was very similar but not identical to the semen from Robert's hand.
This second sample led Dr Whitaker to express doubts about his first analysis and he revised his report, declining to give a statistical likelihood of the sample from Robert's hand belonging to anyone but O'Donoghue.
O'Donoghue's solicitor, Frank Buttimer, had, upon receipt of Dr Whitaker's first report, engaged a forensic science laboratory, Hayward Associates in Cambridge, to examine the DNA evidence.
Upon learning of the semen on the mat, Mr Buttimer advised O'Donoghue's father, Ray, and his two brothers to submit DNA swabs for analysis by a Hayward scientist, who found a perfect match between the mat semen and another family member.
Mr Buttimer made this available to the prosecution and when it was sent to Dr Whitaker, it reinforced his concerns about his initial analysis.The DPP decided it would be unsafe to introduce the sample in evidence.
Detectives asked O'Donoghue what he would say if semen was found on Robert's body, and he replied he was sure they would not find his semen on the body.
Later, O'Donoghue was asked how his semen could have ended up on Robert. He said he must have picked it up from a towel.