The father of Nicola Furlong says it has been difficult hearing the defence in the trial over the death of his daughter in a Japanese court.

19-year-old Richard Hinds who is from Memphis, Tennessee in the US is accused of killing the 21-year-old from Wexford in a Tokyo hotel room last May. His former girlfriend is giving evidence at the trial today.

The doctor who carried out the autopsy on her body gave evidence earlier this week that he believed strangulation was the most likely cause of death. The drugs found in her system have been ruled out as factors in her death.

A friend of Nicola Furlong broke down in court on Wednesday as she re-lived the night she died. The friend who cannot be identified recounted how they both attended a concert in the Japanese capital. Her friend told the court she cannot remember the taxi journey to the hotel where Nicola was found unconscious before she died.

Nicola's parents and sister have been in Tokyo this week for the case.

Her father Andrew Furlong was speaking to Breakfast here on Newstalk. He says it has been tough hearing the defence speak about his daughter and her friend who was there the night Nicola died.