Gda Horkan jury must use ‘common sense’ in weighing up conflicting expert evidence

Judge in Stephen Silver murder trial says it is not ‘trial by expert, this is trial by jury’

Stephen Silver accepts he shot and killed Gda Horkan using the detective’s own gun. Photograph: Colin Keegan/Collins Dublin
Stephen Silver accepts he shot and killed Gda Horkan using the detective’s own gun. Photograph: Colin Keegan/Collins Dublin

A Central Criminal Court judge has told the jury in the trial of Stephen Silver, who denies murdering Gda Colm Horkan, that they must use “common sense” in weighing the evidence of two consultant psychiatrists who differed on the accused man’s mental state at the time he shot the detective.

Mr Justice Paul McDermott told the seven men and five women that they are not bound by the expert evidence and are entitled to prefer one psychiatrist’s evidence over another. He told them that this is not “trial by expert, this is trial by jury” and if they are satisfied that Mr Silver murdered Gda Horkan they must then determine whether his responsibility for the killing was substantially diminished because of a mental disorder.

Mr Silver (46), a motorbike mechanic from Aughaward, Foxford, Co Mayo has pleaded not guilty to the murder of Det Garda Horkan knowing or being reckless as to whether he was a member of An Garda Siochana acting in accordance with his duty. He pleaded guilty to manslaughter by reason of diminished responsibility, at Castlerea, Co Roscommon on June 17th, 2020.

Mr Silver accepts he shot and killed Gda Horkan using the detective’s own gun. Gda Horkan suffered eleven gunshot wounds. Dr Brenda Wright, a psychiatrist called by the defence, said the accused was suffering at the time from bipolar affective disorder, a mental illness that diminished his responsibility.

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Professor Harry Kennedy, who was called by the prosecution, disagreed with Dr Wright and said Mr Silver’s mental capacity was intact at the time of the killing. Mr Justice McDermott told the jury that Mr Silver’s plea means that a not-guilty verdict is not available. For him to be convicted of murder the prosecution must prove that he unlawfully killed Gda Horkan and that at the time he intended to kill or to cause serious injury.

If he is guilty of an unlawful killing but without the necessary intent, he said, they must find him not guilty of murder but guilty of manslaughter. If they find that he had the necessary intent they must then consider whether the prosecution has proven beyond a reasonable doubt that Gda Horkan was a member of An Garda Siochana acting in the course of his duty and that Mr Silver knew that or was reckless as to whether he was a garda acting in the course of his duty. If they find that all those ingredients have been proven then the prosecution has made out the case for “capital murder”, he said.

The defence of diminished responsibility arises, he said, if the jury is satisfied that murder or capital murder has been proven. For the defence to succeed, he said, the accused must first establish that he was suffering from a mental disorder. He reminded the jury that there was evidence that Mr Silver has a diagnosis of bipolar affective disorder. He said the accused must also prove that he had relapsed or was relapsing into an acute phase of the illness at the time of the shooting such that it “substantially reduced his responsibility for the acts at the time”.

If the jury accepts it is more likely that he was suffering from a mental disorder that substantially diminished his responsibility then that reduces murder or capital murder to manslaughter, the judge said. He said they must come to their decision without emotion and by assessing the evidence and the inferences they are happy to draw using their common sense.

He said: “You are not bound to accept the medical evidence which is put forward as expert testimony, you give it such weight as you deem appropriate. If there is other evidence that conflicts or outweighs it or leads you to feel it is not reliable, you are entitled to act on that basis because you are the judges of fact and are entitled to consider the evidence as a whole.”

He asked them to consider whether Mr Silver’s responsibility was diminished and whether it was “substantially diminished” and if the defence has established that it is more likely that it was, then the appropriate verdict would be manslaughter.

He said: “You have to ask yourself, was his responsibility substantially diminished by an operative mental disorder? Was it a real mental disorder, a real contributing factor or cause of his acts at the time?”

He said the jury must also consider the extent of the mental disorder, the extent of its effect on the accused, his decision-making and “in particular his decision to shoot and kill the victim”.

“That is a question for you to assess on all the evidence, in a common sense way, taking into account the medical evidence but also the other evidence which you have heard,” he said.

The jury is entitled to consider the demeanour of the experts in giving evidence and the level of rigour in their approach, he said. Mr Justice McDermott will continue his charge to the jury on Friday.