Prosecutors on Friday sought life imprisonment for a 21-year-old woman charged with murdering an elderly woman and poisoning two high school students.

Lawyers representing the former Nagoya University student, whose name is being withheld because she was 19 — legally a minor — when the incidents took place, have said she cannot be held responsible due to mental illness.

According to the indictment, she strangled Tomoko Mori, then 77, to death with a scarf after beating her with an ax at the defendant's apartment in Nagoya in December 2014. She had become acquainted with Mori when the victim introduced her to a religion.

She was also charged with the attempted murders of a former female classmate from her junior high school and a male classmate from her high school using the poisonous substance thallium between May and July 2012 in Sendai, Miyagi Prefecture.

She "committed (the crimes) with selfish motives. It is vile and she deserves to be strongly condemned," the prosecutors said in a closing statement.

Her defense counsel has also claimed that she had no intention to kill the students.