A former doctor was sentenced on Tuesday to two years and six months in prison for the consensual killing of a woman with a rare neurological disease in 2019 in Kyoto.

The Kyoto District Court found that Naoki Yamamoto, 46, conspired with another doctor, Yoshikazu Okubo, 45, in administering a lethal dose of sedative to Yuri Hayashi, at her request in her apartment on Nov. 30, 2019.

She was suffering from amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig's disease, a progressive neurological disease with no fundamental treatments established.

In February this year, Yamamoto was sentenced to 13 years in prison for killing by unknown means his 77-year-old mentally ill father Yasushi in March 2011, allegedly acting together with his mother Junko as well as Okubo.

Okubo has been indicted in both cases and will be tried separately in January next year.

In handing down the ruling on Yamamoto, Presiding Judge Hiroshi Kawakami said that although the former doctor's role "was limited to keeping watch, he played a significant part."

Yamamoto, for whom the prosecutors were seeking a six-year prison term, said during the trial that Okubo had acted alone with Hayashi's consent.

Hayashi had been living with severe mobility limitations from 2011 and is believed to have wanted to die by euthanasia.

Euthanasia is not legally recognized in Japan. Under the Penal Code, a person who kills another at the request of that person or with his or her consent is liable to a prison term of between six months and seven years.

According to the ruling, Hayashi was administered a fatal dose of barbiturate by the two doctors. She was later rushed to a hospital and died of acute drug intoxication.