Ian Bailey's partner Jules Thomas has begun giving evidence to the High Court.
Ms Thomas confirmed she was also arrested in February 1997 for the murder of Sophie Toscan Du Plantier but told the court that no questions whatsoever were put to her "as to how you did this murder" while she was under arrest.
Ms Thomas is also taking a case for wrongful arrest, which is due to be heard after Mr Bailey's case.
Ms Thomas began her evidence by outlining her education and career as an artist and said she moved to Ireland in the early 1970s.
Ian Bailey told the court earlier he was very unhappy that his private diaries were now being used against him in his civil action against gardaí and the State for wrongful arrest.
His comments came in heated exchanges on what was the final day of his cross-examination.
Mr Bailey told defence counsel Luán Ó Braonáin the fact that his private writings, which were taken from him illegally, had now surfaced in this case was an "absolute intrusion" of his privacy.
The 57-year-old said his personal, private thoughts and words, many of which were written long before the events of 1996, were being "pulled from a hat like a magician pulls a rabbit".
He told Mr Ó Braonáin: "Go on, do what you have to do ... you have your job to do, so get on with it."
Mr Bailey said most of this "is just ramblings and notes and exploration".
Mr Ó Braonáin said the diary entries from as far back as 1989 showed he had a different life from the one he portrayed to the jury at the start of the case.
He suggested Mr Bailey had expressed feelings of being lost and directionless.
Mr Bailey said that was just a possibility of the human condition.
Mr Bailey from the Prairie, Schull in west Cork, is suing the Garda Commissioner, Minister for Justice and the Attorney General for damages in relation to his treatment as a suspect for the murder of Sophie Toscan Du Plantier in west Cork in December 1996.
The defendants deny the claims.
Mr Bailey was asked about diary entries which referred to his smoking and drinking habits.
He accepted he had smoked joints on a regular basis and said it was a common occurrence in west Cork, adding: "Members of the legal profession used to travel down there."
He was referred to diary entries where he wrote about smoking "a wet day J" and he agreed it referred to smoking a joint.
He also agreed he had written that he "ate some hash last night and had enhanced powers of visualisation".
He said this was "to do with imagination, writers have done it for centuries, it helps you to write".
There were other diary entries referring to smoking four to six joints a day.
He said they were very, very small ones and it was many years ago.
Another diary entry referred to "smoking my brains out in some cottage kingdom while the world around me spun out of control".
He agreed he had problems with alcohol but said he had dealt with them years ago.
He said his diary entries were critical self analysis and an effort to improve himself.
One of his diary entries described him getting "strangely drunk and banging his head and fist into a wall".
Another described him as "swinging a blow" at a boy who was bothering him on New Year's Eve.
The diary entries also included references to drinking to excess and being seen as a "foolish bowsy".
It was put to Mr Bailey that this was how he was seen long before the events of 1996.
He said this was more self analysis.
Other entries described how when he had been drinking he had "again hurt Jules".
Mr Bailey said this was a reference to him being cruel with words.
Mr Bailey's cross-examination has now finished after what he said was more than 26 hours in the witness box.
He asked "is that it?" as Mr Ó Braonáin thanked him.
During re-examination by his counsel, Mr Bailey said his alleged informal admissions to the killing were an example of his dry humour.
He said the whole situation was preposterous and that is how he had treated it. He was trying to make light of it with his dry humour.
Any suggestion that he had thrived on the attention were perverse, he said.
He said he spoke to the media to clear his name.
It was pointed out too that a number of other newspaper articles from early on in the investigation which were not written by him contained many details about the killing.
Mr Bailey also said he had "completely addressed" his drink problem in 2001 after a break up with his partner following an assault on her.
He said he attended 120 meetings of alcoholics anonymous in 90 days and then "Jules came back to me and we have been together since."
He said he had used alcohol to relieve the pressure of his situation after his arrest in 1997 and had used it to blot out the reality of the situation.
