Nadine Lott's ex-partner demonstrated to gardaí how he delivered punches down on the beautician as she lay on the ground of her home, a murder trial jury has heard.
The accused, Daniel Murtagh, who said he had boxed "for years", also described to gardaí how he had held a charger for a tyre pump in his hand for solidity and had "wrapped" the wire around his knuckles as he beat Nadine, a garda witness agreed.
Under cross-examination, one of the interviewing gardaí agreed with defence counsel, Brendan Grehan SC, that the accused accepted he might have used the cigarette-type charger "in a hammer action" on the beauty therapist.
During his final interview, Mr Murtagh also told gardaí: "I can box man, I can box. I can take 100kg easy."
Evidence was previously given by Garda Linda Butler, who telephoned ambulance control on the night, that the left side of Ms Lott's face was "extremely and grotesquely swollen" and her left eye was "completely swollen shut".
Gda Butler said she told the controller that Ms Lott had been "beaten to a pulp".
An intensive care nurse at St Vincent's Hospital told the jury Ms Lott was "completely unrecognisable" and that she had never seen anybody so badly injured. "I'm not sure if her left eye was physically present and if the eyeball was punctured," Nurse Leah Grant said.
The jury also heard Ms Lott suffered "severe blunt force trauma" and stab injuries at the hands of her former partner "in a sustained and violent attack" in her Arklow home. It heard evidence that the injuries to Ms Lott were so serious that she never regained consciousness and died three days later in hospital.
A paramedic who attended to Ms Lott at her home had given evidence that the call will "haunt" him for the rest of his career and was one of the most "horrendous scenes" he had ever walked into.
Mr Murtagh, 34, of Melrose Grove, Bawnogue, Clondalkin, Dublin 22, has pleaded not guilty to murder but guilty to the manslaughter of his 30-year-old ex-partner Ms Lott at her apartment in St Mary's Court, Arklow, Co Wicklow, on December 17, 2019.
The jurors spent Thursday morning watching the accused's fourth and final interview, where Mr Murtagh told gardaí that he "went too far with his hand and that's it".
Gardaí put it to the defendant that he was "drip-feeding" information to them about what had happened that night. "I don't know what was going on in my head," replied Mr Murtagh.
In the last interview, the accused calls Ms Lott his "future wife" and said: "Now you're telling me that my future wife to be is barely going to wake up.
"Her friends get battered by their fellas nearly every week," he added.
Recalling the events of the night and pointing to his head, he said "there was nothing there, like".
When asked about a wire belonging to a cigarette charger for a tyre pump, which was found on the sofa of Ms Lott's living room, Mr Murtagh said he had "wrapped" it around his hand.
Gardaí asked how much of the wire he had "wrapped" around his hand as he inflicted the blows on Ms Lott and the defendant said he only remembered "wrapping it".
Mr Murtagh then demonstrated to gardaí in the interview how he wrapped the wire around his clenched fist on the night.
The court previously heard how the accused wrapped part of the wire around his hand to hit Ms Lott, with Mr Murtagh telling gardaí: "It was long and getting in the way when I was hitting her, I stood on it and broke it and wrapped the rest of it around my hand."
During the fourth interview played for the jury on Thursday, Mr Murtagh agreed with gardaí that he also had "the charger part, the connection part" of the pump inside his clenched fist as he delivered blows to his former girlfriend.
"I was going down like that punching," Mr Murtagh said, as he sat forward in his chair in the interview room and punched the air downwards towards the ground.
He agreed he "was striking down" on Ms Lott with his fists as she lay on the ground that night.
As he was speaking, the accused demonstrated by punching his fist into the palm of his other hand.
Gardaí asked at what point did the wire break. "I had a good bit of it wrapped around [my hand] and a lot of it was hanging down and getting in the way so I ripped it off and f****d it away. I wasn't hitting her with the thing that was attached to the pump, it was just the cable," he remarked.
He agreed with gardaí that Ms Lott was lying on her right side with the left side of her face "facing up" as he delivered the blows that night. "But she was looking at me at the same time as well," he continued.
Gardaí read out a doctor's report to the accused during his interview which stated that Ms Lott was in "a serious critical condition" in St Vincent's Hospital with "serious injuries" to her left eye and multiple injuries to her face and neck.
The accused got emotional, put his head in his hands and said: "What can I say, sorry. It's just me in a prison cell now it is."
Defence counsel Brendan Grehan SC cross-examined Garda Barney Carroll, who questioned Mr Murtagh during his interviews. Gda Carroll agreed it was the accused's position that while he admitted assaulting Ms Lott, he did not intend to seriously injure her and it was a "constant recurring theme" that he only intended to give her "a few slaps".
The second matter "which loomed large" in the interviews, Mr Grehan said, was his client's insistence he had only assaulted Ms Lott in the sitting room and not the kitchen.
Gda Carroll also agreed the accused was "severely challenged" on this during his interviews because of the information which the investigation team had at their disposal. He further agreed that Mr Murtagh "absolutely denied" using a pen during the assault and there did not appear to be blood on the pointed bit.
Gda Carroll further agreed with counsel that the accused insisted throughout the interviews that he had only used his fists and "if he repeated that once he repeated it 50 times".
Mr Grehan said the cigarette charger for the tyre pump only arose in the last interview, when the accused said he had it in his hand when he was beating Ms Lott. The witness agreed with the barrister that the accused described to gardaí how he held the charger in the centre of his hand for "solidity" and the wire was wrapped around the outside of his knuckles.
Gda Carroll also agreed the accused accepted that he might have used the charger "in a hammer action" to injure Ms Lott.
Gda Carroll said that when Murtagh was shown a picture of the cigarette charger belonging to the tyre pump, he recalled having the charger in his fist and described how he broke the wire off and wrapped it around his hand.
Mr Grehan put it to the witness that the charger was "pretty bloodied and all over the main part", where a cigarette lighter would go. "The whole part was covered in blood," replied the witness.
Gda Carroll said a piece of the wire which was originally connected to the cigarette lighter and the end piece of the wire, which was attached to the pump, were both located on the sofa in the living room.
Mr Grehan said his client had "pressed fairly hard" and never "wavered" from the position that he did not know how Ms Lott ended up in the kitchen.
Gda Carroll agreed the accused had "steadfastly maintained" that he had not assaulted Nadine in the kitchen and she was in the living room and still breathing, when he left that night.
"The only suggestion was perhaps she made her own way to the kitchen and collapsed there and he couldn't give any explanation as to how came to be there," added Mr Grehan.
Finally, Gda Carroll agreed with Mr Grehan that the accused was adamant nothing would have happened on the night if he was sober, not taking drink and drugs and had been let "sleep it off" on the couch.
The court heard Mr Murtagh's four interviews had concluded before Ms Lott passed away.
Detective Garda Michael Hall told Mr Grehan there was no indication that a large kitchen knife found underneath the sofa had ever been used that night.
In the fourth interview, gardaí also asked Mr Murtagh if he was "p****d off " because Ms Lott was not replying to his messages and "probably down the town with the other man".
He said this had not "triggered" it all off but he was a little bit hurt. "If she had just let me asleep it would have been grand, the fact she woke me up and I got all threats off her. She was hell bound saying 'get out of this house'," he added.
The accused said he knew he was going to jail for "a stupid thing I've done but I didn't mean to do it, that's the God's honest truth".
He said he would love gardaí to get into his head and have "a little wander to see" why he did it.
Gardaí put it to the accused that text messages from Ms Lott to him could not have been any clearer. "You can think of it that way if you want but there is nothing more that I can say to you. We were having sex every time we bumped into each other. It was getting stronger and stronger and she was afraid it was going to get out," he replied.
Just under two weeks before Mr Murtagh killed Ms Lott she told him in a WhatsApp message not to "threaten" her and that "nothing is ever going to happen between us again, I want to make that clear".
When gardaí put it to him that their relationship was not official, Mr Murtagh said of course he loved Ms Lott but he still needed "a bit of sex don't I".
The trial continues on Friday before Mr Justice Michael MacGrath and a jury of seven men and five women, when it is expected that the prosecution will close its case.