Question: What is the last name of the person who admitted injecting HIV-contaminated blood in the milk cartons of the two students who she claimed to have murdered her daughter? If there is no answer, please output "Insufficient information to provide an answer.". Movie title: Confessions Context: Junior high school teacher Yuko Moriguchi (Takako Matsu) announces to her class that she will resign before spring break. Moriguchi reveals that because the HIV-positive biological father of her daughter Manami was ill, she used to bring Manami (Mana Ashida) to school with her. One day, after school, she returned to the room where Manami was but found her gone. Her daughter was later found drowned in a school swimming pool. She then explains that two pupils in her class, whom she dubs "Student A" and "Student B", have murdered her four-year-old daughter. She had found a small bunny purse amongst Manami's belongings which should not have belonged there, which led her to question Shuya, one of her students. Shuya, who immediately admitted killing Manami, mocked her compassionate reaction to his feigned expression of remorse with "just kidding". Having revealed their identities, she explained that because the killers, as minors, are protected by the Juvenile Law of 1947, turning them in wouldn't make a difference. So to exact revenge on them, she admits injecting her late daughter's biological father's HIV-contaminated blood in the milk cartons of the two students who she claimed to have murdered her daughter. The rest of the film switches between the aftermath of Moriguchi's confession and the events before the confession through a series of first-person narratives from Moriguchi and her three students. Naoki Shimomura (Kaoru Fujiwara), Student B, becomes a shut-in because he believes he has acquired AIDS from drinking HIV-contaminated milk. His mother (Yoshino Kimura), after spotting the hidden malicious messages in well-wishes cards from Naoki's classmates, realizes her son was somehow involved with an earlier incident. She decides to commit murder-suicide to free her son and herself from torment, but in the ensuing struggle, Naoki kills her. The police arrest him for the murder. Shuya Watanabe (Yukito Nishii), Student A, explains that his mother abused him before leaving to pursue her scientific ambitions....
Moriguchi