The architect’s murder trial also heard yesterday that paint on a spade discovered near Ms O’Hara’s remains did not match paint found in Mr Dwyer’s garden shed.
Forensic scientists provided the evidence the day after Mr Dwyer’s wife, Gemma, said that she recognised the spade as one missing from their garden, referring in particular to “splatters of orangey red paint on it”.
Mr Dwyer, aged 42, is charged with murdering Ms O’Hara at Killakee, Rathfarnham, on August 22, 2012, hours after she had been discharged from a mental health hospital.
The Cork-born father of three, of Kerrymount Close, Foxrock, Dublin, has pleaded not guilty to murdering the 36-year-old childcare worker on that date.
The trial is entering its 27th day at the Central Criminal Court.
Dr David Casey of the Forensic Science Laboratory testified that he examined items from Ms O’Hara’s home for biological substances, including blood and semen, for the purpose of DNA profiling.
The first item he dealt with was a mattress which had five stab cuts and three small holes. These were mainly at the top end of the mattress, a photograph of which was shown on screens throughout the court-room.
He said semen was found in five areas of the mattress, but it was not possible to say when it had been deposited.
Dr Casey said that a full DNA profile matching that of the accused was found on three of those areas. He found partial DNA profiles matching Mr Dwyer’s on the two remaining stains and on a non-semen-stained area.
He said there was no evidence of a DNA profile from another source (person).
The scientist also examined blood staining on the mattress. Again, he was not able to say when the blood had been deposited. He said that out of four areas of blood staining, two had holes. “The DNA profile from those matched that of Elaine O’Hara,” he said.
He sampled five areas of blood staining on a beanbag cover and the DNA profile matched that of Ms O’Hara. He said there was also a stab cut to this material.
He did not find any semen on the inside of a black dress and there was insufficient DNA for profiling on the inside of a gas mask. He found a mixed DNA profile from two people on a rope from the apartment.
Dr Casey also examined items found with Ms O’Hara’s remains in Killakee. These included black tracksuit bottoms, which had three holes to the back, right buttock, and upper thigh as well as a hole in the crotch area.
He was unable to rule out animal interference as the cause of the damage and found no semen or blood on the garment.
He identified no blood on a spade found at a second location in Killakee and proceeded to examine its handle for skin cells. He found partial DNA profiles from at least two people but these were unsuitable for further interpretation.
The witness explained that the absence of semen or blood from the items was not significant, given their exposure to the elements for such a long period of time.
Bridget Fleming of the Forensic Science Laboratory testified that she was asked to examine tubs of paint and protector from Mr Dwyer’s shed, a piece of fence from his garden, and a spade found near Ms O’Hara’s remains.
She said her examination was to see whether any paint traces on the spade could be from the same source as the paint on Mr Dwyer’s fence or the paint in his shed.
“They appeared like dried-on paint droplets,” she said of brown stains on the spade.
She carried out both microscopic and chemical composition tests. Under the microscope, she said the appearance of the paint on the spade was similar to that from Kerrymount Close.
She said they were also similar in chemical composition, but differences were observed.
“They did not match,” she said.
Ms Fleming said she was also asked to compare a rope found in Ms O’Hara’s home with pieces of a rope found in Killakee. “They were different,” she said.
The jury also heard yesterday from two chief superintendents, who had requested information on a total of five phone numbers from certain mobile-phone companies.
The jury then heard from an engineer whose company works on behalf of the phone companies regarding data collection.
Conor O’Callaghan of Vilicom Engineering Ltd said that he had produced engineering information for hundreds of unique cell IDs. He explained that this included locations and directions of mobile phone antennae.
He said he also generated coverage plots for dozens of individual cells. The jury was shown some of these plots on maps of the various sites mentioned in the trial.
Mr O’Callaghan will continue his evidence today.
The trial has heard that Ms O’Hara was last seen in Shanganagh, south Dublin, on the evening of August 22, 2012. A cause of death could not be determined when her skeletal remains were discovered at Killakee on September 13 the following year.
It is the State’s case that Mr Dwyer stabbed her for his own sexual gratification.