Stephen Silver, whose defence will argue that he was suffering from a relapse of a mental illness when he shot Detective Garda Colm Horkan, was "out of touch with reality" in the hours after the shooting, a doctor has told the Central Criminal Court.
Dr Greg Kelly, a general practitioner, told defence counsel Róisín Lacey SC that he spoke to Mr Silver in the early hours at Castlerea Garda Station shortly after the shooting.
The doctor was concerned that the accused was hitting his head off the cell wall and said he "came to the fairly rapid decision that this man is not well. He wasn't reacting normally for someone involved in such a tragic and serious event".
He described Mr Silver as restless, agitated and speaking so quickly he was "passing himself out".
He appeared to be paranoid and at one point refused a glass of water because he believed it was poisoned.
His reaction to what had happened seemed "fairly bizarre and unreal", the doctor said, adding that such behaviour is often seen in people in the "manic phase of bipolar disorder".

Dr Kelly gave Mr Silver 50 milligrams of an anti-psychotic. He visited the station again later that morning and told gardaí that Mr Silver was fit to be interviewed but recommended that he be assessed by a psychiatrist. The doctor also contacted the Central Mental Hospital.
Dr Kelly told Ms Lacey: "I knew they were the experts in this type of situation. I had formed the opinion that a psychiatrically ill person had committed the most serious crime you can commit, had killed an innocent garda doing his duty, so I was very anxious to get this right and to ensure that the proper procedure was carried out."
Stephen Silver, aged 46, a motorbike mechanic from Aughavard, Foxford, Co Mayo, has pleaded not guilty to the murder of Det Gda Horkan on 17 June 2020 at Castlerea, Co Roscommon.
He is charged that he committed the murder knowing or being reckless as to whether Det Gda Horkan was a member of An Garda Síochána acting in accordance with his duty. He pleaded guilty to manslaughter by reason of diminished responsibility.
During the opening of the trial, prosecution counsel Michael Delaney SC told the jury that the defence will argue that Mr Silver was having a relapse of his mental health issues at the time of the shooting and that his culpability is therefore substantially reduced.
Dr Kelly told Ms Lacey that at about 3pm the following afternoon he saw Mr Silver again and this time found him "calm and laid back".
He didn't seem concerned and said that he would be "out of here this evening". Dr Kelly thought his demeanour was not normal and that he was "out of touch with reality".
At one point he complained that gardaí did not get him a cup of tea and said that this was "the main reason" for gardaí being there. Dr Kelly said this was another indication of his "detachment from it all", that he was acting like he was in a hotel looking for room service.
Dr Kelly told prosecution counsel James Dwyer SC that when Mr Silver was calm, he told him that before Covid he had been getting on well but "everything went wrong after that". He had been living in a shed and had not been sleeping or taking his medication.
Dr Kelly said Mr Silver probably was not getting the proper surveillance that a person in his position needs and that psychiatric services were being done over the phone which was of "very limited value for psychiatric patients".
Earlier today the jury heard from State Pathologist Dr Linda Mulligan who told Mr Delaney that Det Gda Horkan was shot 11 times, once from a distance of 30cm or less, and suffered catastrophic and non-survivable injuries. He died from multiple gunshot wounds with no other contributing factors.
Prior to Dr Mulligan's evidence, Ms Lacey made a formal admission that a further injury noted by the pathologist to Det Gda Horkan's eye and temple was inflicted by the accused "as a result of a blow by the butt of a gun".
The trial continues in front of Mr Justice Paul McDermott and a jury of seven men and five women.