A man charged with the murder of his partner's mother told gardaí he had done "something terrible" when he walked into a garda station after body parts were found in the Wicklow Mountains.

Kieran Greene, 34, denies murdering Patricia O'Connor, on 29 May 2017.

The Central Criminal Court heard he was very upset when he told gardaí in Rathfarnham on 12 June that "the stuff up the mountains" was him.

But at that stage gardaí believed the body parts belonged to a man in his 20s.

Garda PJ Foley told the court he noticed a man sitting in the waiting room of Rathfarnham Garda Station at around 7.15pm on the evening of 12 June 2017.

He said he wanted to speak to someone in charge and claimed the body in the Wicklow Mountains was that of Mrs O'Connor.

The court has heard 15 parts of Mrs O'Connor's body were found in nine locations in the mountains between 10 and 14 June. However, the initial information the gardaí had was that they were those of a young man in his 20s.

Sergeant Lucy Myles then spoke to Mr Greene. He said he had done something terrible and "the stuff up the mountains was me".

Asked what he meant, he said he meant the body parts scattered in the mountains. He said he cut them up and threw them "all over the place up there".

He told Sgt Myles the person he cut up was his mother-in-law.

He said he was not married to her daughter, but had been with her for ten or 11 years and had three kids. Mr Greene handed the sergeant the keys to the car he said he had used to bring the body away.

He said he was getting out of the shower when Mrs O'Connor came in and started shouting and screaming at him.

Mr Greene claimed she picked up one of the kids' hurls outside the bathroom door and started hitting him.

He grabbed her and hit her back and he said all he remembered was coming around and she was lying on the floor with blood everywhere.

Mr Greene said he had put her in the boot of the car and brought her to Wexford, where he buried her in a shallow grave.

But a few days later, he said he panicked, dug her up, cut her up and scattered her in the mountains.

Gardaí searching for Patricia O'Connor in the Wicklow Mountains (Photo: RollingNews.ie)

Sgt Myles said she was aware body parts had been found, but that initial post-mortem results indicated the body may have been a male in his 20s. She was also aware Mrs O'Connor had been reported missing.

The sergeant said she took a voluntary cautioned statement from Mr Greene. She described him as very upset and very fidgety.

In his statement, he said he felt terrible with what he did and he described how they had been "fighting over the cat".

He said Mrs O'Connor had stormed out of the house earlier in the night, but had returned around midnight.

He said she opened the bathroom door, hit him with the hurl and was saying "get out, get out".

He said he really did not know what happened, but woke up, saw blood everywhere and panicked.

Mr Greene described burying Mrs O'Connor in a shallow grave in Wexford, but he said a few days later, he panicked and went back again with a hacksaw.

He tried to move her but could not, so he cut her up and scattered pieces in the mountains.

He said he had tidied up and touched up paint in the house and cleaned the blood up with a mop and water.

Under cross-examination from Mr Greene's defence counsel, Conor Devalley, Sgt Myles agreed that the implication of Mr Greene's account was that he had done all this completely on his own.

She also agreed that "a veil was drawn" over the "fatal act" in which Mrs O'Connor died.

The court heard detectives decided to interview Mr Greene further and get a detailed account from him. They interviewed him that night and again the following day.

Mr Greene told gardaí he could not live with the guilt. He said it was eating him up, he could not sleep; he felt sick, weird and horrible and kept seeing his kids' faces.

He told them that on 29 May, after the row, he said he remembered waking up and Mrs O’Connor was on the ground.

Patricia O'Connor lived at this house in Rathfarnham

Mr Greene said he thought he saw his dead uncle who said everything would be alright. He said he panicked and decided to bring her upstairs to her bedroom.

He said it was a "bleeding miracle" he got her upstairs as she was heavier than he was, but after around an hour he brought her downstairs again and put her in the boot of the car.

Mr Greene told gardaí he had just panicked. He said it had been a long ten years. In a way, he said, he felt safe, as she was not going to hurt the kids or pick on them.

He said he could not let her hurt them anymore. It was that bad, he said, they tried for help and everything.

He sobbed as he said if he could take it back he would. He told gardaí that Mrs O'Connor was verbally abusive on a constant basis. He said she was always threatening to have them killed and said she wanted them out and him gone.

Mr Greene said he put her body in the car and did not know what he was going to do. He decided to keep going and ended up in Co Wexford.

He found a field, dug a hole with his hands, put her body in the hole and covered it up.

He said he went back to move the body after five to seven days because it was playing on his mind that she might be found and he did not think that would be fair on Louise, the kids, or the farmer in whose field he had buried her.

Mr Greene said he returned to the scene where he had buried the body. His plan was to wrap her in black bags and just move her, but he said he could not move the body.

Gardaí at the scene in Wexford

He said he decided he had to chop her up to make her lighter. All that was going through his head was the kids, he said. He put the body parts in black bags and loaded them into the car.

He drove initially past the Hell Fire Club in the Dublin Mountains and at a point past there he opened one of the bags and dropped the body part into a ditch.

He said he pulled in five or six times and left a body part each time until everything was gone, as well as the clothes he had been wearing and the tools he used.

He said he got back into his car and sobbed and sobbed. He said the kids did not have to worry anymore and he was finally free. Asked what he was free from, he said: "All the torment and pain she caused, the verbal, giving out to the kids."

Detective Garda David Connolly said Mr Greene agreed to go to Wexford with gardaí and point out the field in which he had buried Mrs O’Connor.

When they reached the field, Garda Connolly noticed a disturbed area of ground consistent with what Mr Greene had told them and he could see what appeared to him to be hair.

He arrested Mr Greene for the murder of Patricia O'Connor at that stage.

The case will continue tomorrow.

Mrs O'Connor's daughter, Louise, her former partner, Keith Johnston and their daughter, Stephanie O'Connor have all pleaded not guilty to impeding the apprehension and prosecution of Mr Greene.