LAST UPDATE | 17 Nov 2022

A JURY AT the Central Criminal Court has failed to reach a verdict in the trial of Stephen Silver, who accepts that he shot Detective Garda Colm Horkan 11 times but denies his murder.

The jury were asked to consider whether Silver was suffering from bipolar affective disorder at the time of the shooting and whether his condition substantially reduced his responsibility for the killing. Silver’s lawyers argued that he should be found not guilty of murder but guilty of manslaughter due to diminished responsibility.

The seven men and five women spent just under nine hours considering their verdicts over three days before revealing that they had a disagreement that they were not able to resolve.

The case will now be listed again at the Central Criminal Court on 9 December next and Silver will be sent forward for a retrial. He has been remanded in custody until that date.

Mr Justice Paul McDermott thanked the jury for what they had done over the last number of weeks.

“This was a very difficult case in detail and evidence and the nature of the case itself. It was very disturbing for everyone, especially for people such as yourselves who had to be judges,” said Mr Justice McDermott.

“I want to thank you for your application, attention, and dedication, and for the significant contribution you have given,” he said, excusing the panel from jury service for the next ten years.

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

Silver accepts that he shot and killed Garda Horkan using the detective’s own gun. Garda Horkan suffered 11 gunshot wounds. Dr Brenda Wright, a psychiatrist called by the defence, said that the accused was suffering at the time from bipolar affective disorder, a mental illness that diminished his responsibility. Professor Harry Kennedy, who was called by the prosecution, disagreed with Dr Wright and said that Silver’s mental capacity was intact at the time of the killing.

Mr Justice Paul McDermott told the jury that for the accused to be convicted of murder, the prosecution must prove that he unlawfully killed Garda 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 Garda Horkan was a member of An Garda Síochána acting in the course of his duty and that Silver knew that or was reckless as to whether he was a garda acting in the course of his duty. If all those ingredients had been proven then the prosecution would have made out the case for “capital murder”, he said.

The defence of diminished responsibility arises, he said, where a 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 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 had accepted that it is more likely that he was suffering from a mental disorder such that it substantially diminished his responsibility then that would reduce murder or capital murder to manslaughter, the judge said.

Jurors

Mr Justice McDermott asked the jury to come to their decision without emotion and by assessing the evidence and the inferences they were happy to draw using their common sense.

He told the jurors they were not bound by the expert evidence and they were entitled to prefer one psychiatrist’s evidence over another. This was not “trial by expert” but trial by jury, the judge reminded the panel.

He added: “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 added: “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?”

They must 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”, the judge said.

“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.”

Evidence

The trial heard that Silver had been prescribed Olanzapine, an anti-psychotic drug, following his previous admission to a psychiatric hospital in September 2019. He told the trial that he stopped taking his medication within days of leaving the hospital, as he had done following his 16 previous admissions since 1997.

Silver said that he now recognises that in the days leading up to the shooting he was becoming unwell and he now accepts that he needs to take his medication. He said he hadn’t been sleeping well and was becoming “talkative, talking gibberish” and had fleeting thoughts that a woman he was seeing was an MI6 agent. He also believed, he said, that the SAS might have planted a bomb under his van.

On the day of the shooting, a friend showed Silver a video on his phone of a raid by armed gardaí on the home of a mutual friend, James Coyne. Silver, who hadn’t seen Coyne in more than 10 years, called into his old friend and later gave him a motorcycle which was worth, according to Silver, €2,500. He said that if he had been well he would never have given away the “prized bike” which he had spent years working on.

That night Silver and Coyne drove the motorcycle at speed without a light or helmets through the Knockroe estate where Coyne lived. Silver did a “burnout” on the back tyre and was heard by one neighbour to shout: “I dare the armed squad come down here now.”

The prosecution alleged that he was “filled with a burning anger” towards gardaí and was trying to provoke a confrontation.

Silver said that he was unwell and that he had no interest in a confrontation with gardaí. He said his thoughts were confused at the time. Silver and Coyne later put the bike away and walked towards Castlerea town centre shortly before midnight to get a pizza. The streets were empty due to a Covid lockdown in place.

Garda Horkan, who had responded to calls by Knockroe residents about the disturbance caused by Silver, pulled up in his unmarked Garda car behind Silver and Coyne at the junction of Patrick Street and Main Street. Silver told the trial that he noticed the passenger side window was down and that the driver was staring at him.

In his direct evidence to the jury, the defendant said: “So I put my head down to the window and he asked me who I was.” Silver said he gave the man his name and asked who he was and heard him say that he was a garda, just as Garda Horkan was getting out of the car.

Garda Horkan was wearing a Tommy Hilfiger jacket which Silver said he thought was “strange” and not something a Garda would wear. He said he didn’t believe he was a Garda and added: “He came around the front of the car, round the bonnet, and he came at me very quickly, he was within a few inches and squared up to me as if to start a fight.”

Silver said he told Garda Horkan to keep two metres away, as per the Covid prevention guidelines, and Silver put his right hand up “to keep him at arm’s length”. Silver said he then relaxed and put his arms down at his side. “I thought there was going to be no hassle and I wanted to see what this man wanted,” he said.

He said Garda Horkan, “just grabbed me” and they started grappling. Garda Horkan, he said, tried to get a grip of his left arm and Coyne tried to pull Silver back, causing the accused to fall to the ground. Silver said the struggle continued and he tried to get back up by putting his hands on Garda Horkan’s hips and that’s when he felt the gun holster.

He told the jury: “That gave me a fright and I thought this was some kind of assassination attempt. Why did he have a gun? I put my hand back to see if the gun was there and his hand was on the gun. We started struggling to try and get the gun and the gun came out of the holster and both our hands were on it.”

Silver said his hand was on the handle of the gun and Garda Horkan’s hand was around his hand. He added: “Next thing, I pulled the trigger and nothing happened so I pulled it again and it fired, a loud pop noise. I pulled my hand off it and Colm fired it twice.”

Silver said: “Colm’s hand started to lose power, falling away from the gun. I took the gun on my own then, Colm started to fall backwards. I hit him on the head with the butt of the gun on the side of his head.”

He said it happened so fast he had no time to think, adrenaline was flowing and, he said, he was trying to protect himself. “I didn’t know who he was, I thought it might be a drug dealer that James knew. I thought it might be something to do with James. I thought it was unreal that someone had tried to attack me with a gun.”

He said he also believed that Garda Horkan’s unmarked Hyundai with its Dublin registration plate might have followed him from Dublin that day. He said: “I had a lot of confused thoughts about the situation. I was just trying to get free of the situation. I felt I was in danger, but it happened so fast it was very, very, very frightening.”

In his Garda interviews, Silver claimed that Garda Horkan had attacked him, tried to kill him and at one point claimed that Garda Horkan had shot himself. His behaviour during his interviews was described as aggressive, hostile and bizarre.

He described his victim as a “prick” and a “dirtbag” and insulted the detectives interviewing him. At one point he told them: “One of your guys died, accept it and move on, there’s no case to solve,” and described Garda Horkan as “fumbling around like a fucking eejit” with his gun.

When he took the stand Silver apologised for his behaviour and said he would not have spoken like that if he had been well.

Injuries 

State Pathologist Dr Linda Mulligan told the trial that Det Garda 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.

Dr Mulligan documented fractured bones, spinal injuries and damage to the liver, kidneys, lungs, abdomen and heart, all caused by the 11 gunshot wounds. One bullet entered the stomach, went through the diaphragm, across one chamber of the heart, tore the aorta, entered the right chest cavity causing an injury to the back of the lung and exiting at the back of the neck. The injuries caused by this wound were not survivable, Dr Mulligan said.

At the entry point of the same wound Dr Mulligan found suet and “powder tattooing” which she said is caused by exposure to materials that are burned when a bullet is fired. She said their presence around the wound indicate that the shot was fired from a distance of 30cm or less. One other shot showed suet but no powder tattooing, indicating it was fired from a distance of more than 30cm but less than one metre. Other shots were fired from a distance greater than one metre, she said.

Some of the exit wounds had a “shorn” appearance, she said, which suggest that Garda Horkan was on the ground when he sustained those injuries.

James Dwyer SC, for the prosecution, said that Silver was “filled with a burning anger” towards gardaí because he believed they had unfairly targeted his old friend James Coyne. He said that Silver had tried to “retrofit” mental illness into the case after reviewing the book of evidence.

Defence counsel Roisin Lacey SC said that Silver’s bizarre behaviour in the lead up to and aftermath of the shooting, particularly during his garda interviews, showed that he was suffering a relapse and should be found guilty of manslaughter rather than murder.

Psychiatrists

The trial heard from consultant psychiatrists who differed over the extent of the impact that Silver’s mental disorder had on his actions at the time of the killing. Dr Brenda Wright said that a defence of diminished responsibility would be appropriate but Professor Harry Kennedy said there was no evidence that Silver was delusional at the time of the killing.

Professor Kennedy pointed to evidence which he said showed Silver was capable of complex sequences of purposeful actions such as taking control of the gun, pulling the trigger, standing back, supporting the gun with both hands, pointing and aiming and choosing to fire at Garda Horkan’s trunk. The professor said the capacity to form intent can be inferred from purposeful actions, where a person does “one thing after another after another”.

Professor Kennedy said there was further evidence that when gardaí arrived at the scene moments after the shooting, Silver was able to make a decision to obey gardaí by getting on the ground but also decided to what extent he would cooperate when he refused to be handcuffed around the back but allowed gardaí to handcuff him to the front. Professor Kennedy said this was a decision made for his own comfort and based on his past experience dealing with gardai. His interactions with gardaí showed that he was able to act in his own interests, Professor Kennedy said.

In his Garda interviews Silver showed “strength of will”, resisted attempts by gardaí to build rapport and showed himself to be “not at all suggestible”, Professor Kennedy said. At one point he feigned sleep for several minutes while gardai asked him questions, the professor said, showing an “intact ability to act reflectively and not impulsively and having regard to his own best interest as he sees it”.

He said that “fleeting” ideas Silver had the day prior to the shooting about an MI6 agent and the SAS were not fixed false beliefs and therefore not delusions.

He said that Silver had a “long experience of behaving in a disruptive way” that required his family or members of the public to call gardaí. It was his “learned impunity”, the professor said, that caused him to become more irritable and angry as gardaí continued to detain and question him following the shooting.

The Professor explained: “He had learned that he could expect not to be charged and, at most, to be treated in a psychiatric hospital. His surprise and outrage at being detained and interviewed is therefore understandable because of this learned impunity.”

He added: “Over time if a person learns that what they do doesn’t have consequences, they will continue doing it.” He said he saw nothing to indicate delusions or hallucinations during Silver’s interviews, although Silver did speculate about conspiracies. Delusions are “fixed false beliefs”, he said, whereas Silver described his theories as possibilities.

The defence called Dr Wright, who told the trial that Silver’s “bizarre” behaviour on the night and in the following days were evidence that he was suffering a relapse of bipolar affective disorder. She said his capacity was reduced by his mental disorder and that a verdict of diminished responsibility would be appropriate.

Dr Wright found that Silver’s illness was “secondary” to his failure to take medication that had been prescribed to him after he was hospitalised eight months before the shooting. The doctor agreed under cross-examination, however, that Silver had repeatedly decided not to take medication over many years, despite medical advice.

She said that the accused’s aggression and hostility towards investigating gardaí, grandiose ideas and disinhibited behaviour were possible symptoms of an abnormal mental state or a manic mental state.

Dr Wright said she had watched DVDs of Silver’s interviews with gardaí in which he claimed to be a captain in the 62nd Cavalry of the Connaught Rangers, warned a detective to “sit down before you’re put down” and described Garda Horkan as a “little dirtbag that got shot with his own fucking gun”.

She said such behaviours during interviews and other behaviour noted by gardaí and a doctor on the day of the shooting were bizarre and inappropriate to the situation he was in. His aggression and hostility, she said, did not reflect the behaviour of gardaí, who acted appropriately throughout.

Silver was later admitted to the Central Mental Hospital where he was diagnosed with bipolar affective disorder which is being treated using Olanzapine. He was transferred to Mountjoy prison in 2021, where his condition was described by Dr Wright as normal.

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