The Irish woman, who was with Nicola Furlong on the night she was killed, has told a Tokyo court about her alleged sexual assault and the rape and murder of her friend, earlier this year.

The unnamed witness spoke, via video link, about the evening of May 24th, when she and her friend, Furlong, had attended a Nicki Minaj concert. Furlong was later found murdered in Keio Plaza Hotel, an upmarket establishment.

Both Irish women were living in Japan as part of a study abroad exchange.

A 19-year-old American musician has admitted to strangling Furlong but denies his intent to kill.

Read more: Family of Nicola Furlong, Irish student murdered in Japan, speak of the heartbreak

Another American, James Blackston (23), is being charged with “quasi-forcible indecency” after allegedly assaulting the witness in a taxi on their way to the hotel.

The witness was in tears speaking to the court. She said that that night had “changed everything” for her.

She told Judge Masayuki Yamada, “I feel anxiety and I find it hard to breathe…I wish we had not trusted these two men because they have just wrecked everything.”

She told the court that on the night of Furlong’s murder they had been approached by the two American men at a train station.

The witness recalled, “They were nice and friendly.”

The Irish Times reports that the group of four went to the entertainment district of Shibuya. The danced and drank in a club.

According to the witness, Furlong declined the invitation to stay at the men’s hotel. She explained to the men that they would return to their university dormitories on the first train after they had enjoyed a good night together.

The witness said, “They said we could have one room and they would have the other…We said, ‘No way, we’re fine thank you.’ We just thought they were being friendly.”

It is believed the women were drugged at the bar and bundled into a taxi. CCTV footage from the Keio Plaza hotel shows the suspects wheeling the Irish women through the lobby and into their rooms.

In court the witness confirmed that she blacked out after the nightclub.

She said, “We went to the toilet and when we came back there were four drinks there on the bar counter. I have no memory of what happened after that.”

When she awoke Furlong was being put into an ambulance.

The defense aimed to establish that the women were drunk before the assault. The witness denied this.

She declined to look at stills taken from security cameras, after the nightclub. She said it was “too hard.”

“Me and my friend lived together and we always did things together,” she said.

“Now she’s gone and she’ll never come back.”

The accused, Blackston, is also charged with the assault of another woman earlier this year. If convicted of the Irish woman’s assault he could face up to ten years in prison.

The trial for Furlong’s death begins in March 2013.

Read more: Murdered Irish student’s heartbreaking text to mother - friend remembers little of tragic night