Witness Marie Farrell has walked out of the witness box at the Ian Bailey case.
Ms Farrell had been asked to name the man she was with on 23 December 1996 when she saw another man on Cealfada bridge before the murder of Sophie Toscan Du Plantier.
She had previously told the court that the man in whose car she was travelling was not her husband and she did not want anyone to find out who she was with.
She repeatedly refused and when told by the judge to answer the question she said she wanted nothing more to do with this and walked out of the witness box.
Counsel for the State Paul O Higgins asked her to tell the jury who the man was as he could shed light on the case.
“I’m not going to tell you that” she replied.
Mr Justice John Hedigan had told Ms Farrell that this was one of the most serious cases to be heard in many years and that she was obliged to tell the truth.
“Now answer the question,” he said.
Ms Farrell said: “I’m going, I’m having nothing more to do with this.”
She stood up from the witness box and walked out of court.
The case has now proceeded with the next witness, Saffron Thomas, who is the daughter of Jules Thomas, Mr Bailey’s partner.