Prosecutors on Friday demanded the death penalty for a former nurse, accused of killing three patients by putting a disinfectant into their intravenous drips at a Yokohama hospital in 2016.

Ayumi Kuboki, 34, has admitted to acting with premeditation in mixing an antiseptic solution into the drip bags, causing the patients to die, in a high-profile lay judge trial at the Yokohama District Court.

Prosecutors pointed out that while the defendant exhibited traits of autism, she was fully competent to stand trial, and the disorder did not affect her decision-making or play a part in her carrying out the crimes.

The defense counsel argued in the trial that Kuboki had diminished capacity at the time of the crimes brought on by schizophrenia.

According to the indictment, Kuboki killed three inpatients — Sozo Nishikawa, 88, Asae Okitsu, 78, and Nobuo Yamaki, 88 — at the then-Oguchi Hospital, by injecting disinfectant into their IV drip bags in September 2016 with the intention of killing them.

Prosecutors said Kuboki set the timing of the IV drips so that the patients would die after she was already off duty to avoid having to deal with the families over their deaths.

"She acted very selfishly ... although she was in a position to protect people who are socially vulnerable," prosecutors said.

Ahead of the prosecutors' arguments, Nishikawa's daughter gave a statement before the court.

"I can hardly think the defendant felt remorse over what she did. I want her to atone for her crimes with death," she said, referring to the defendant who repeatedly responded, "I do not remember," during questioning.