Prosecutors in Japan have demanded a 6-year prison sentence for a former doctor accused of killing a woman with a progressive degenerative disease at her request.

Forty-six-year-old Yamamoto Naoki is charged, together with fellow doctor Okubo Yoshikazu, aged 45, with killing 51-year-old Hayashi Yukari in Kyoto City in 2019. Hayashi was suffering from amyotrophic lateral sclerosis, or ALS. The two men have been indicted for consensual homicide.

Prosecutors say the defendants administered a chemical to put Hayashi to death.

Yamamoto has entered a not-guilty plea in the court proceedings so far. He insisted that although he was at Hayashi's house at the time of the crime, he did not kill or conspire to kill her.

At the Kyoto District Court on Tuesday, prosecutors said it is not conceivable that Yamamoto, who accompanied Okubo to the crime scene, had been unaware of the homicide plan.

They said even if the victim had wanted to commit suicide, the defendants decided when to kill her and that the matter was a malicious act.

The defense counsel said Yamamoto ended up acting as a lookout, but that he had no idea what Okubo was planning to do.

Yamamoto said he does not understand why he is accused of committing the crime with Okubo. He said he wants the court to make a decision based on evidence.

The court will hand down the ruling for Yamamoto in December.