Graham Dwyer told gardaí he did not kill anyone after he was arrested on suspicion of the murder of Elaine O'Hara in October 2013.
He told gardaí he did not murder Ms O'Hara.
The court has been hearing details of interviews carried out by gardaí with Mr Dwyer after his arrest at his home shortly after 7am on 17 October 2013.
Sergeant Peter Woods said he cautioned him. In response, Mr Dwyer said: "I don't know what you are talking about."
He was brought to Blackrock Garda Station.
Sgt Woods said he told Mr Dwyer in the patrol car that he should consult a solicitor.
He said he had been arrested for the most serious offence that a person could be arrested for.
He said he told Mr Dwyer he needed to take proper legal advice and asked him to instruct his solicitor fully.
In the first interview, Sgt Woods asked Mr Dwyer if he knew Ms O'Hara.
He responded that he did not kill anybody.
He repeated this several times and told Sgt Woods he was worried about his wife and his job.
He was asked about his work, his interest in cars and model aeroplanes and his family life.
There was a long discussion about how gardaí investigate crimes.
Mr Dwyer told Sgt Woods that he would love to know how he was associated with this.
When DNA testing was explained to him, he said he understood all of this. But he said he did not kill anyone.
He said he was in the station. He wanted to know why he was there and when he could go home.
He said he did not mind giving a DNA sample as he did not kill anyone.
Later he told gardaí he would do anything to help but the advice he had got was that if he did not kill anyone, to say he did not kill anyone.
He said he was worried about being associated with this case.
He was worried about his wife and work. He said he was worried his photo would be taken and wanted nothing to do with this case.
He asked would he still have a wife if he is associated with this case. Who would employ him?
He was told gardaí had a very good, clear and accurate picture of Ms O'Hara's life over the last two years and that she had intended to work at the Tall Ships festival before she died.
He replied "it's tragic". He was told they knew a lot about her sexual history. He said he was listening.
He said a person's private life should be their private life.
He said he did not want to be on any tabloids.
Mr Dwyer said if he was even remotely associated with this he would jump in the river, if he was not able to have his wife's trust or his job.
He said he definitely did not kill anyone. He said he did not want to lose Gemma.
Second interview
In his second interview, he said he did not murder Ms O'Hara and he said he would like to know how his life had been ruined by this case.
Mr Dwyer told gardaí that the only person he knew in Stepaside was an old school friend.
Shown a picture of Ms O'Hara, he said he saw it. He said he was not going to tell any lies or mistruths.
He said he was not a killer and not a saint.
He told gardaí they were trying to make him guilty of something he did not do. He said if his job and family were not the same he had nothing to live for.
He was asked if he could remember where he was on 22 August 2012, the day Ms O'Hara disappeared. He said he could not.
He was shown stills from CCTV footage of a man at Ms O'Hara's apartment block on various dates and was told his work phone was in the Stepaside area at the same times.
He said he was glad he was not murdering anyone in any of the photos.
He repeated that he did not kill anybody. He asked was there anyone else on the CCTV.
He said he never denied being in Stepaside or in the shop at Belarmine Plaza.
He asked if anyone else had been arrested for murder. I don't know what you are doing. Is it stalking?, he asked.
He also denied that an 083 number and an 086 number the gardaí say were used by him to contact Ms O'Hara were his.
He told the gardaí they were making huge assumptions.
Mr Dwyer was asked by Sgt Woods if he ever contacted Ms O'Hara on any website.
He replied: "I see why you knocked on my door. That's better." He said again he did not kill anyone.
He said he could see why he was a person of interest, he told gardaí they were making huge assumptions.
He told them he would like them to use their technology to check his mobile phone and see where that had been.
Third interview
In his third interview with gardaí, Mr Dwyer again repeatedly said he did not kill anyone. He also denied sending the text messages which have been read to the jury.
He was asked if he knew anything about master and slave. He replied "not at this time."
He said he was thinking about his wife and kids.
He said: "I did not kill anyone. I'm happy with that."
Sgt Woods began reading excerpts to Mr Dwyer from the text messages gardaí had recovered at that stage.
These are some of the text messages read to the jury during the last three days.
Mr Dwyer said repeatedly that it was not him. He repeatedly said it was not his phone.
When he was shown a print out of Elaine O'Hara's diary which said "Graham's number" and the 083 number beside it, he said he could not explain that. But he said it was not his phone. It does not make sense, he said.
Asked if he had a stabbing fetish, he said: "Oh my god. That is not my phone".
As further excerpts from the text messages were read he asked repeatedly asked gardaí to stop and said he was "mortified" and said gardaí were trying to upset him.
He said it was "awful stuff".
He said he could not explain how the 083 phone was registered to his sister's address.
At one point when the text messages were being read, he said "that is nuts". He said he did not want to talk about his sex life. He asked gardaí to stop.
He said he could not explain a text from the 083 phone in which the person came fifth in flying.
"Oh my god" he said "that's not me. You are trying to disgust me. I can't explain these things. It's not me. It's not me."
He told gardaí that anyone who knew him knew he would not hurt anyone.
He told gardaí the texts were not relevant.
Sgt Woods said they were very relevant. Mr Dwyer told him they were reading the texts to shock him.
Sergeant Woods asked him if it was shock that they had the texts. Mr Dwyer said no. It was not his phone.
Mr Dwyer told Sgt Woods he had been looking at horror scenes from horror movies the night before he was arrested. He said it was "erotic horror" sort of art to do with horror.
He said he was mortified to describe it. He told gardaí they were trying to upset him.
The court heard he was looking at pictures of women with knife wounds.
Sgt Woods also put it to Mr Dwyer that his ex-partner Emer McShea had made a statement that he started to bring a knife into the bedroom.
Mr Dwyer said she was probably delighted that he was in trouble.
He said he did not own the bag that was found in the reservoir in Roundwood and that he was seen carrying on CCTV footage in August 2012. Asked if he could elaborate, he said he could not.
When he was told gardaí had found his DNA in Ms O'Hara's apartment, he said he understood.
He said he hoped they did have his DNA so they would know he did not kill anyone.
He said he was not an innocent person but "I'm not a murderer".
He said he was confident he did not kill anyone.
He told gardaí he would not air his dirty laundry there.
He said he thought he knew what was coming but he did not want his wife hurt.
He said he wanted to protect her.
Warning: Graphic content
Earlier, Sgt Woods confirmed that the two people seen in three videos watched by the jury earlier this week were Mr Dwyer and Ms O'Hara.
The jury saw nine explicit video clips earlier this week.
Sgt Woods said he had watched all the other videos found on hard drives at Mr Dwyer's home.
He said they all showed sexual activity with either the use or pretended use of a knife.
He also said a video was found which showed Mr Dwyer putting a plastic bag over Ms O'Hara's head and sealing it with a cable.
He said at a certain point, Ms O'Hara went limp and fell to the side.
Fourth Interview
In the fourth interview, Mr Dwyer again insisted the text messages weren't written by him. He said he couldn't explain them.
In this interview he discussed his relationship with Ms O'Hara.
He said the rucksack found in the reservoir belonged to Ms O'Hara in which she would keep her BDSM gear.
He said she may have wanted it moved while she was in hospital.
He said he met her a long time ago. He said he contacted her through a website.
He said he had wanted to keep this from his wife.
He said he met Ms O'Hara a few times over the years. Mr Dwyer told gardaí that he wouldn't cut anyone. He wouldn't blood let. He said it was power, fantasy, makebelieve.
He said that she had asked him to kill her at one stage.
He said when he heard she had gone missing, he knew something had gone awry.
He said he did not think he had a key to her apartment.
He said he couldn't explain how he was seen on CCTV leaving Ms O'Hara's apartment on 13 August with the bag later found in the reservoir.
He said he would have contacted her by text but again repeatedly denied the phones which sent texts to Ms O'Hara were his.
Mr Dwyer told gardaí he thought long and hard about talking about the sex stuff.
He said he didn't really kill anyone.
Asked what he meant by that, he said he really didn't kill anyone.
Asked how he got into Ms O'Hara's apartment when she wasn't there, he said he didn't know. He couldn't help the gardaí.
He said they had been suggesting stuff all day to him and he had had to keep on his toes. I didn't kill Elaine O'Hara.
He said Ms O'Hara had scars on her because she had harmed herself.
