[9][10] Kamata visited the bar as well, and came across the woman, whom he invited to have a meal and some drinks with two other people, but by the end of the night, he brought his drunken acquaintance back to his condominium.
[12] The second victim was a 19-year-old college student, who went missing after she left her dormitory at around 17:00 on April 16, 1985,[13] while en route to her job as a dry cleaner for a treatment facility in Tondabayashi.
Early next morning, the victim's remains were discovered near the Miyoshi family's farm in Kōryō, Nara Prefecture, who immediately notified the district police about the gruesome discovery.
[17] Three months after the finding, on September 6, Kamata sent a taunting letter to the police chief, signed "The Monster with 22 Faces" (alluding to the Glico Morinaga case), postmarked from Sakai.
In the letter, Kamata provoked police by telling them to "catch [him], if they can", naming the sushi restaurant that he took the victim before killing her and what body parts he had cut off,[19] providing information only the killer could have known.
When the Nara Prefectural Police traced the girl's whereabouts on the day of her supposed disappearance, they learned that she had been seen visiting the exact same sushi restaurant with an unidentified middle-aged man.
[20] Around 17:30 on January 22, 1987, Kamata stopped a 9-year-old walking home from school, ostensibly to ask her for directions towards the Sumiyoshi Grand Shrine and pay her 200 yen,[21] whom he then kidnapped.
[22] After killing her, he discarded the body in the mountains, and then called the Sumie Elementary School four or five times, where the victim was attending, requesting them to prepare a ransom of 30 million yen in exchange for the girl.
On April 4, 1994,[28] an investigator from the Minoh Police Department, while searching for the body of Kamata's fifth victim, was examining the cypress forest grounds.
[37] During the investigation stage, Kamata admitted to all of the crimes, except for the ransom letter in the schoolgirl murder, but when put on trial, he proclaimed his innocence and alleged that a friend of his was the real killer, and he had simply helped dispose of the remains.
[38] The phone call recording would later be played in court, with the prosecutors claiming that it was very similar to the defendant's voice, but Kamata's attorneys demanded a re-evaluation of the evidence.
In response, the court contacted Matsumi Suzuki, the company director of the Japan Acoustic Research Institute, who conducted a voiceprint test on the suspect.
In connection to that, the prosecutor pointed out that the ruthless nature of the murders, Kamata's antisocial behavior and his request for the death penalty to be applied as a just punishment for his actions.
[45] Immediately after the ruling, Kamata announced that he would appeal his conviction to the Osaka High Court, citing his acquittal of the ransom charge as proof that he was innocent.
[54] On June 6, 2005, the appeal trial for the Supreme Court, presided over Judge Hiroshi Fukuda was held, with the defense counsel again presenting their narrative that their client had simply helped dispose of the bodies, and was not a murderer.
In 2016, Minister of Justice Mitsuhide Iwaki signed the death warrant for Yasutoshi Kamata, and on March 25, 2016, he was executed by hanging at the Osaka Detention House.