Man said he 'smacked' granite stone off grandfather's head before using cement block to 'finish it off'

Alison O'Riordan

A native Irish speaker described to gardaí how he "smacked" a granite stone off his 78-year-old grandfather's head outside his home in the Donegal Gaeltacht before using a cement block to "finish it off", a Central Criminal Court jury has heard.

Opening the prosecution's case on Monday, Patricia McLaughlin, along with Fiona Crawford, told the trial that the accused Derek Mulligan was the victim of serious sexual abuse at the hands of a school caretaker when he was a child and has suffered with a litany of mental health difficulties since his teenage years.

McLaughlin said that expert consultant psychiatrists for both the State and defence are in agreement that the accused was suffering from a mental disorder when he killed his grandfather.

Mulligan (39), with an address at Carrickcoyle, Derrybeg, Gweedore in Co Donegal, has pleaded not guilty by reason of insanity to the murder of his grandfather Derek Burns (78) at Carrickcoyle on December 19th, 2023.

Giving evidence on Tuesday, Detective Garda Paul Dolan, of Milford Garda Station, told McLaughlin that officers arrested Mulligan and interviewed him three times. He said the accused admitted assaulting his grandfather and causing the injuries that led to his death.

Interviews

In his interviews, Mulligan told gardaí he had gone to his grandfather's on December 17th to be somewhere safe, as he was sitting in his own house when "black spiders" started to appear on the roof. "I was only going up there for a visit like," he said.

Mulligan said he just went up to Burns' to get "a fag" off him but his grandfather was in no mood to talk to him. He called the deceased "a grumpy old bast**d" but went on to say: "I love my grandad, he is all I had left, he is the only one I had left."

The accused told gardaí that he could hear a lot of voices in his head and they were saying "you have to kill him, you have to kill him".

Mulligan told himself that he was not going to hurt an "old man" but that he "just grabbed him" and threw Burns to the ground. The accused said he had "kinda lost it" and was "battering and battering and battering" his grandfather.

He said he gave Burns a couple of kicks when he was on the ground. He also said he had thrown a rock and brick at him.

Asked what had he thrown at him, the accused said "I hit him in the f**kin head man". He said "as an old man of course he went down straight away".

Asked how many times he had hit him, the accused said 10. The accused said he was scared of himself when he snapped and that he "always" heard voices. He said he was only at his grandfather's house for three minutes and that he now felt guilty and sad.

The accused told officers in his second interview that he was walking away when "something said you have to finish him off". He said he then picked up a granite stone, went back to his grandfather and "smacked it" off his head. He said it had taken two hands for him to carry the stone.

I was demented like I was just a possessed man.

The accused said he had tried to stab his grandfather with a pitchfork before he got the stone but it wouldn't go through the body and was "bouncing off him", so he threw it away. "I tried putting it through his head but looked like it was just bouncing like he had rubber skin or something".

"I was demented like I was just a possessed man," the accused said.

Mulligan said he picked up "a cement block to finish it off" and threw the block on his grandfather's head. He said all he could see was blood coming out of Burns' head.

The accused told gardaí he had gone off his medication about three months prior to this and thought by doing this, it would "see his nana proud of him".