A Japanese court on Tuesday sentenced a 48-year-old woman to life in prison for killing in 2018 her diabetic father by overdosing him with insulin, as well as murdering her brother and disguising his death as a suicide.

The Osaka District Court found Akemi Adachi guilty in a case where prosecutors had sought the death penalty and had claimed the defendant showed an extreme disregard for life.

Adachi gave her 67-year-old father, Tomio, who also had cancer, excessive doses of insulin in January 2018 at his home in Sakai, Osaka Prefecture, according to the indictment. He died five months later from encephalopathy caused by low blood sugar.

Photo taken Oct. 13, 2020, shows the Osaka District Court in western Japan. (Kyodo)

She also forged a suicide note by her 40-year-old brother Masamitsu that admitted to administering insulin to their father.

According to the indictment, Adachi gave her brother sleeping pills before taking him to a bathroom and burning charcoal, causing him to die from carbon monoxide poisoning in March 2018.

Her defense counsel had argued she was innocent as she had no motive for murder.

Adachi has remained silent since the investigation.

The defense counsel said Tomio had died from cancer, as opposed to an overdose of insulin, while pointing to the possibility that Masamitsu was killed by an outsider, citing a difference in physique between him and the defendant.