Mr Ian Bailey confessed to the murder of Ms Sophie Toscan du Plantier to a 14-year-old schoolboy with the words, "I bashed her f**king brains in", a court heard yesterday.
Mr Malachi Reed told Cork Circuit Court that he placed bolts on the doors of the family house after Mr Bailey made the comments to him while receiving a lift home.
The claims were heard on the seventh day of a libel trial where Mr Bailey is taking seven defamation actions against eight newspapers over articles which he says linked him to the murder of Ms Toscan du Plantier.
Mr Reed said the incident occurred some time after the murder of Ms Toscan du Plantier and Mr Bailey appeared to be in an angry mood in the car.
"He was anxious, preoccupied, cursing with himself. I asked him how work was going. He said fine, until I went up there with a rock and bashed her f**king brains in.
"I got a cold shiver and nervousness, and I stayed quiet for the next two miles," Mr Reed said.
A day later he told his mother about the incident and put bolts on all the inside doors of the house. Mr Reed said that ever since Mr Bailey had made the comments, he would "jump over the ditch" to avoid taking a lift.
Mr Reed's mother, Ms Irene Amanda Reed, said her son was still upset by the remarks. As a mother on her own with two children in the house, she felt "terrified" by Mr Bailey's comments and had locked the doors of the house ever since.
"Mr Bailey has a tendency to do unpredictable things. He's an unusual person," Ms Reed said.
Mr James Duggan, counsel for Mr Bailey, said Mr Reed was mistaken and that Mr Bailey was despairing about what people were saying about him and had not confessed to the murder. "Are you seriously suggesting he said that?" Mr Duggan asked.
"Do I look serious?" Mr Reed replied.
"And why would he say that?" Mr Duggan asked.
"I've asked myself the same question," Mr Reed said.
A local man, Mr Ritchie Shelly, also told the court yesterday that Mr Bailey had confessed to the murder on New Year's Eve 1998, with the words: "I did it, I did it. I went too far." Mr Shelly said he and his wife, Rosie, had been invited back to their house for drinks late that night.
He said Mr Bailey spent most of the night discussing the murder of Ms Toscan du Plantier and showing them newspaper clippings of the murder.
When Mr Bailey went about organising bedding for them to stay the night, Mr Shelly said he and his wife, who felt uncomfortable about the topic of conversation, decided to phone for a lift.
When Mr Shelly went into Mr Bailey's bedroom to find the phone, he said Mr Bailey, who had drifted off to sleep, woke up and was crying.
Mr Shelly said: "He put his arms around me and said some words, 'I did it, I did it'. Then I asked: 'You did what?' He said: 'I went too far.'" Mr Duggan, counsel for Mr Bailey, said his client was despairing that "they" were saying he did it and suggested that Mr Shelly had forgotten this detail.
Mr Shelly replied: "I'm not forgetting it. I'm not lying. I've no reason to lie." Mrs Rosie Shelly, who was standing in the kitchen at the time, said she heard the same words as her husband.
"It was clear and succinct," she said. "It seemed like a kind of confession," she told the court.
The Paris correspondent for the Observer newspaper, Mr Paul Webster, also told the court that a man purporting to be Mr Bailey had contacted him before his arrest and claimed that he had met Ms Toscan du Plantier. "He made it absolutely clear he had talked to her - I've no doubt about at that at all - and saw her on the day she died. That's what I was given to understand," Mr Webster said.
Mr Webster said Mr Bailey said that Ms Toscan du Plantier was "more of an acquaintance than a friend". Mr Bailey, however, has insisted that he told Mr Webster that he "knew of" Ms Toscan du Plantier.
A photographer, Mr Michael MacSweeney, also told the court that Mr Bailey told him by phone on the day of the murder that his girlfriend had taken photographs of the murder scene at 10 or 11 a.m. Mr Bailey, however, claims they took photographs of the scene after 2 p.m. when he says he first heard of the murder.