The trial of a man accused of murdering Irish woman Nicola Furlong in Tokyo has heard the evidence of an expert witness called by the defence.

Richard Hinds, 19, from Memphis, Tennessee in the US, is accused of killing Ms Furlong, a 21-year-old Co Wexford student, in May of last year.

On the fourth day of the trial, Dr Marianne Hamel from Pennsylvania challenged some of the findings of the autopsy report.

Dr Hamel said at the outset that she did not think Dr Kenichi Yoshida, who performed the autopsy on Ms Furlong's body, had made any mistakes.

She also agreed that Ms Furlong's neck had been strongly forced.

However, she disagreed on two points. She said she thought the influence of alcohol and the drug Xanax in Ms Furlong's bloodstream had lessened her suffering.

Dr Hamel also said she could not tell if the strangulation had been done manually or using some ligature, such as a towel.

She said none of the classic features of either manual or ligature strangulation were present in this case.

The trial also heard a statement read into the court from a member of the band for which Mr Hinds played keyboards.

Backing dancer Dmac Sandoz, who was staying in the same hotel as Mr Hinds, phoned his room at around 3am.

The phone was answered by a woman, whom he described as "relatively drunk".

A short conversation ensued until the accused came on the line and told Mr Sandoz that he was okay and it was just a woman he met.

"She's tripping," he told Mr Sandoz.

About 30 minutes later, Mr Hinds phoned Mr Sandoz to tell him the woman had "passed out" and that he "didn't know what to do".

Mr Sandoz went to Mr Hinds' room to find Ms Furlong on the floor and Mr Hinds "paralysed with fear".

He later went on to describe Ms Furlong and her friend as "party girls", by which he meant he thought they must have taken drugs.

Ms Furlong, from Curracloe, had been living and studying 100km north of the capital, at Takasaki City University of Economics, as part of an exchange programme from Dublin City University.