In the spring of 1971 young women in Gunma prefecture were being stopped on the street by a man in a beret and a Russian peasant blouse who drove a white Mazda rotary coupe. He said he was an art teacher, sometimes gave his name as Watanabe Yaichi, and asked them whether they would model for a painting. Many got into the car. Between March 31 and May 10 he killed eight of them, and buried their bodies in cleared building land and fields around the prefecture. They were sixteen to twenty-one years old, and six were minors. He was Kiyoshi Okubo, thirty-six, unemployed, and newly out of prison on parole.
He was born on January 17, 1935, in Yawata village in Usui district, now part of Takasaki. By his own family's account his parents indulged him without limit, and his mother went on calling him by a baby name after he was grown. He was convicted of rape again and again from his youth and served several prison terms. The car he cruised in had been given to him by his parents.
On the evening of March 31 he drove to the car park outside Shinmachi station to meet a seventeen-year-old he had taken for a drive before. She arrived with three friends, and he made an excuse and left. That night, in Tano district, he killed a seventeen-year-old high school student. On April 6 he killed a seventeen-year-old waitress in Takasaki, and on April 17 a nineteen-year-old temporary worker at the prefectural office in Maebashi. Five more followed before May 10. The women he killed, by the account that emerged, were those who refused him or saw through the story. One other woman was injured and survived.
He was caught because the family of one of the missing women went looking for her themselves. A relative had memorized the number plate of the car she was last seen in, reported it to the police, and went straight to a Mazda dealership to ask for help. The owner turned out to be Kiyoshi Okubo of Yawata-machi, Takasaki. On the strength of his own admissions and witness accounts the police took out a warrant for kidnapping for indecent purposes and arrested him on May 14, 1971, four days after the last killing. Two and a half months of interrogation followed before he led investigators to all eight graves.
The Maebashi District Court sentenced him to death on February 22, 1973. His lawyer, Shigeru Machida, said afterward that he regretted never hearing him apologize. Okubo did not appeal, and the sentence became final when the time limit ran out on March 9, 1973. He was hanged at the Tokyo Detention House in Kosuge on January 22, 1976, at forty-one. The Yomiuri Shimbun's report the next morning said he had shown no remorse to the end. The name of the eighth victim is given as Naoko Takanohashi in some lists and Naoko Ishizaka in others.