The man accused of murdering Nicola Furlong in Japan last year has said he "had no intent, motive or reason to hurt, harm or kill" the Wexford woman.
On the first day of the trial in Tokyo, Richard Hinds, aged 20 and originally from Memphis in the United States, denied her murder.
Ms Furlong was found dead in the Keio Plaza hotel in Tokyo's Shinjuku district on 24 May, 2012.
Mr Hinds told the court he did "lightly press" Ms Furlong's neck but he did not believe he was the cause of her death.
His defence counsel added that the cause of Nicola's death was unclear and there was a "strong possibility" she may have died from alcohol and other drugs.
The prosecution said Mr Hinds had shown no remorse and they would prove that he had strangled her using a towel.
Two witness statements were read out from bar workers at the nightclub where Nicola and her friend went with Mr Hinds and his friend, James Blackston, after a concert.
The barman said the four had ordered three tequila shots as well as a round of vodka and Red Bull.
The manager of the bar also described seeing one of the young women collapsed on the floor of the toilet.
Security footage from the taxi the four took to the Keio Plaza Hotel was also played in court.
The Furlong family could see the footage but the rest of the court could only hear it.
The two men spoke about having sex with the young women. The women seemed to be unconscious in the taxi.
Nicola's parents Andrew and Angela along with her sister Andrea have travelled to Japan for the trial.
Mrs Furlong became visibly upset at times while the tape was played out.
DNA evidence from the crime scene was also presented to the court.
Traces of both Ms Furlong’s and the accused’s DNA were found on a towel in the hotel bedroom where her body was found.
Bloodstains were also found.
Blood tests taken from Ms Furlong showed the presence of alcohol as well as traces of the drugs xanax and lidocaine.
The day ended with the testimony and cross-examination of the night manager at the Keio Plaza Hotel.
Takuya Niwano told the court how he helped put the girls into wheelchairs when one of them collapsed in front of the lifts.
He also described going to Room 1427 following a complaint about noise. When he was outside the room, he heard a voice in English saying: "She's no breath."
He went inside to find Mr Blackston and Mr Hinds in the room with Ms Furlong collapsed on the floor.
He attempted CPR and called for an ambulance.
The case will run for two weeks and the judge said a verdict will be delivered on 19 March.
Mr Blackston has been accused of sexually assaulting Ms Furlong's friend.
The verdict in his case will be delivered tomorrow.