A barrister and law professor told gardai that he had been “terrified and stressed” and was acting in self-defence when he shot another man at his farm in Dublin almost three years ago.

Diarmuid Rossa Phelan, 56, is charged with murdering 36-year-old Keith Conlon at Hazelgrove Farm, Kiltalown Lane, in Tallaght, on February 24 2022.

On the first day of the trial, the jury of nine men and three women heard the opening address from Roisin Lacey SC for the Director of Public Prosecutions (DPP).

The Central Criminal Court in Dublin was told that Phelan shot Mr Conlon, who was a trespasser on his land, in the back of the head as he turned to walk away.

Diarmuid Rossa Phelan, 56, is on trial in Dublin charged with murdering 36-year-old Keith Conlon at Hazelgrove Farm (Brian Lawless/PA)

The trial, which is expected to last six weeks, heard details of the events which led up to the death of Mr Conlon.

It is the prosecution’s case that Phelan pointed the gun at Mr Conlon and shot him in the head and that the accused intended to kill.

The defence will argue that Phelan shot the victim in self-defence and that he was shot accidentally due to fear, stress and the movement of the victim as well as the inaccuracy and light weight of the weapon.

The court was told that on the afternoon of February 22 2022 Phelan was working on his farm with four farmhands when he heard a dog barking nearby.

The accused went in the direction of where he heard the dog and was accompanied by one of the farmhands. The court also heard that Phelan took a firearm, a Winchester rifle, with him.

Ms Lacey told the jury that there were three trespassers on the accused’s land who had been there without permission and had been there to take part in fox-bolting, which is the hunting of foxes and badgers.

It was explained to the jury that the process involves sending a small dog, wearing an electronic tag, down a hole to find either a fox or badger, and then capturing the animal.

The three men – Mr Conlon, Callum Coleman and Robin Duggan – had two dogs with them and were in a wooded area on the accused’s land.

The court heard that Mr Coleman’s pet dog had been tied by a leash to a tree when, shortly after 1pm, the accused shot the dog dead.

The prosecution claimed that the accused did not issue any warning before he shot the dog and that no words were spoken in relation to the shooting.

Mr Coleman and the others heard the gunshot and then saw the accused and the farmhand and noticed that Phelan was carrying a rifle.

There was a heated exchange between them, with Mr Conlon and Mr Coleman shouting at the accused.

The court heard that Mr Conlon took out his phone and took a video of the encounter, which the jury will be shown during the trial.

On the first day of the trial, the jury of nine men and three women heard the opening address from Roisin Lacey SC for the Director of Public Prosecutions (Niall Carson/PA)

The accused and the farmhand retreated to an open area where the other three farmhands were.

Mr Conlon and Mr Coleman followed them a short time later and emerged from the wooded area, and were shouting at the accused, saying they would call gardai about the dog.

Phelan told the two men that he too would call gardai. He shouted at the men to keep their distance and to get back but Mr Conlon, who was ahead of Mr Coleman, continued to approach the accused as Phelan walked towards them.

It was at this point, the court heard, that the accused took out a Smith and Wesson revolver from the pocket of his jacket.

The accused fired three shots quickly, two of which were fired into the air while the third hit Mr Conlon.

Neither Mr Conlon nor Mr Coleman had weapons with them, the court was told.

It is the prosecution’s case that Mr Conlon had turned away from the accused when he was shot in the back of the head. The entry wound was 3cm behind his right ear.

Mr Conlon fell to the ground into what was once a golf bunker. The court herd that he fell face forward but, despite being shot, he could turn on to his back.

After seeing what happened, Mr Coleman ran away.

Three separate phone calls were made to emergency services, including one from Phelan about the dog, another from the farmhand and later Mr Coleman to report that his friend had been shot.

The court was told that after the shooting, Phelan left the rifle in his bedroom and got a first aid kit and returned to the scene.

Emergency services arrived at the scene where they found the victim alive but in a critical condition.

Mr Conlon was treated by gardai with blood-clotting powder to the wound.

The court heard that Phelan told gardai that he shot Mr Conlon and when asked where the gun was, he took it out of his pocket and threw it on the ground.

Mr Conlon was taken to Tallaght hospital shortly after 2pm and put on life support.

The court heard that he underwent two rounds of brain stem tests and was discovered to be brain dead. He was pronounced dead shortly after 3pm on February 24.

Diarmuid Phelan is on trial for the murder of Keith Conlon (Sam Boal/PA)

A pathologist reported that the victim had a fracture to his left shoulder as a result of falling forward and a single gunshot wound to the back of the head. The bullet had gone through Mr Conlon’s brain but did not exit the head and the bullet was recovered during the post-mortem examination.

Phelan was arrested and taken to Tallaght garda station where he was questioned by gardai.

Phelan, who denies murder, told gardai that there were previous incidents of trespassers on his land including ones with dogs.

He said that he put up fences around his property but they had been broken down and that he was concerned about lambing ewes on the other end of his farm.

He said that after hearing the dog barking, he went to the wooded area with a farmhand and had called out twice asking if someone was there and raised his voice, but there was no reply.

He told gardai that he saw a dog, which was loose, and shot it.

He said that the three men “exploded” from the bushes and were roaring and shouting about the dog, saying they would “get him”.

Phelan said he believed what they were saying were threats, and felt he had to get out of there, and he was stumbling and shaking as he made his way up the bank.

Phelan said he went to other farmworkers and asked them to call gardai, and it was then that he was alerted to the “travellers” coming towards them.

Ms Lacey told the court that the two men were not travellers.

Phelan said he told the men to stay back but they had come forward and he was worried they would fulfil the threats they had made.

It is claimed that Phelan walked towards the two men, pointed the gun over their heads and shot into the air three times. He said he was stunned when Mr Conlon went down.

He said he had the revolver for vermin control.

Phelan said that if he had not acted immediately, the other man would have got him. He said he was “terrified, stressed and scared shitless”. He said he was not angry and did not lose his temper.

He told gardai that he was entitled to discharge the weapon as this was done in self-defence.

Phelan said it was done without the intent of causing the bullet to penetrate the body of Mr Conlon, that it happened accidentally and that it was an unintended result.

He said that it was done due to fear and stress and the movement of the man.

Ms Lacey said it is the prosecution’s case that the accused intended to kill Mr Conlon.

The trial continues on Thursday.