The former policeman whose bus rampage caused the death of a 62-year-old mother was a paranoid schizophrenic who believed he was being pursued by several police forces and intelligence services.
Peter Clarke, a former City of London Police constable, had been diagnosed years before the bus incident both here and in the USA as psychotic and was suffering from a mental disorder at the time, Dr Henry Kennedy, Clinical Director of the Central Mental Hospital, said on day-three of his trial.
"He knew what he was doing but he didn't have the mental capacity to understand the consequences of his actions," Dr Kennedy said at Dublin Circuit Criminal Court.
Dr Kennedy said that while he believed Clarke was fit to plead and stand trial, he continued to hold false delusions about gardai and police forces as well as intelligence services like MI5 in several jurisdictions and about his fellow-workers.
He held "paradoxical beliefs" about being a member of the IRA and the police. "He said he wanted to be killed and also wanted to kill all his perceived persecutors in the services and among his fellow-workers."
Dr Kennedy said that as a result of his "persuasive delusions" Clarke "was unable to refrain" from doing his actions on the day of the rampage.
"Schizophrenia is a disease for life. It doesn't go away but is manageable and can be controlled."
Dr Kennedy said Clarke won a UK£7,500 court settlement for racial discrimination in the London Police force in 1994 but lost another case when he wasn't admitted to the British Transport Police.
Clarke (aged 38) of Kiltalown Court, Tallaght is on trial on charges arising out of what the prosecution has described as "an odyssey of destruction" resulting in Ms Maire Buckley's death on May 07, 2006.
Ms Angela Buckley told prosecuting counsel, Ms Pauline Walley SC, she had been travelling with her mother to a First Holy Communion restaurant meal and was applying makeup and chatting when she saw a man run towards the traffic at Bluebell screaming at people to get out of their cars.
Ms Buckley said her mother pushed her free of their Nissan Micra car before the collision but couldn't get out of her driver's door because the car was beside the LUAS stop railing, ahead of the oncoming bus.
Ms Buckley said she got her Seattle off first and her mother, who was "half in, half out" of the driver's door when the bus struck, had her hand against her, pushing her out of the car.
Ms Buckley said when she was free of the car, the bus was initially coming for her but changed direction slightly and hit the car. "By the time I got out and began running, the bus was gone."
Detective Sergeant Sean Hogan told Ms Walley that Clarke struck him on the head with an axe when violently resisting arrest after the bus crashed onto an embankment at Dualway's depot in Rathcoole.
"I've never dealt with anyone as strong or as violent in my service in the Garda Siochana."
Detective Sgt Hogan said he chased Clarke to the Dualways depot after his rampage through west Dublin and lured him towards the yard embankment to prevent him from escaping back onto the road.
He said he got out of his car, stood in front of the embankment and began waving his arms "frantically" at Clarke who had turned the bus around and was accelerating back towards the yard entrance.
Detective Sargeant Hogan said Clarke drove at him and he jumped out of the way before the bus's nose crashed into the embankment. "I stood my ground as long as possible, that was my get-out clause."
He said he rushed onto the coach before Clarke could put it in reverse and saw him halfway down the bus corridor. Clarke swung around and struck him on the head with an axe.
Detective Sargeant Hogan said several gardai struggled to restrain Clarke and they had to prise his fingers individually from the dagger he was holding. Clarke had him pinned him down and lunged with his head and bit him twice on the hand during the struggle and he had to hit him "forcefully" with a baton.
Ms Caroline Cummings BL (with Ms Walley) read statements from other witnesses who had been on the LUAS stopped at the Bluebell stop and saw the Ms Buckley roll under the bus.
Triona Murray, a hairdresser, reported that she saw people jumping over the LUAS railings to dodge the speeding bus which was travelling the wrong way down the Naas Road outbound.
She saw the lady come out of her car and fall under the bus and when it passed she ran to the spot where the lady lay but realised instantly she was dead because her body was black from the bus and road impact.
Ms Cummings also read out the conclusions of the Deputy State Pathologist's post-mortem examination conducted on the deceased the following day.
Dr Michael Curtis concluded that Ms Buckley died instantly of "multiple, catastrophic injuries" to her head, chest, pelvis and lower limbs.