Joji Obara

Former prosecutor Takeshi Tsuchimoto, now a professor of criminal procedure law at Hakuoh University Law School, criticised the decision to acquit Obara for the murder of Blackman by pointing to the conviction of Masumi Hayashi due to circumstantial evidence. The public prosecutor, however, appealed the Blackman-related verdicts, as crucial forensic evidence had not been heard at the original trial, and on March 25, 2008, an appeal trial commenced in the Tokyo High Court. Tokyo's High Court found Obara guilty on the counts of abduction, dismemberment and disposal of Blackman's body on December 16, 2008. In early December 2010, the Supreme Court of Japan rejected Obara's appeal and upheld his life sentence.

On February 9, 2001, Blackman's dismembered body was found, buried in a shallow grave under a bathtub in a seaside cave at Miura, Kanagawa, about 50 kilometres (31 mi) south of Tokyo, just a few hundred meters from Obara's apartment. The body had been cut into eight pieces, her head had been shaved and encased in concrete, and was too decomposed to show the cause of death. According to Obara's indictment, he made Blackman a drink containing a drug before raping her at a condominium in Zushi, subsequently killing her. Obara has maintained his innocence, claiming the drugs that caused her to die were voluntarily self-administered.

In October 2000, Obara was charged with drugging, raping and killing Blackman, as well as with raping eight other women and the manslaughter of Ridgway. His trial began on July 4, 2001, and on April 24, 2007, he was jailed for life on multiple rape charges and manslaughter, but was acquitted of Blackman's rape and murder due to a lack of direct evidence. Evidence supporting his guilt of rape included the approximately 400 videos he took, which showed him engaged in date rape activities (including one with Ridgway). For the charge of manslaughter, the prosecutor produced an autopsy report showing traces of chloroform in Ridgway's liver and a paper trail showing that the accused accompanied her to the hospital before she died. In Blackman's case, however, the prosecutor could not produce any forensic evidence linking the accused to her death. Even her cause of death could not be determined.

Lucie Jane Blackman (September 1, 1978 – July 1, 2000) was an English woman from Sevenoaks, Kent who worked as a hostess in Roppongi, Minato, Tokyo. Blackman had previously worked as a flight attendant for British Airways and went to Japan to see the world and earn money to repay her debts. At the time of her disappearance, she had been working as a hostess at Casablanca, a nightclub in Roppongi, later called Greengrass. On July 1, she went on a dōhan (paid date) with a Casablanca customer. Other than a few calls to a friend during the date, no one heard from her again.

Carita Simone Ridgway (March 3, 1970 – February 29, 1992) was an Australian model from Claremont, Perth, Western Australia, who was working in Tokyo's Ginza area as a bar hostess to earn money for acting school. Common in East Asian nations, "hostess" in this sense describes a modern form of geisha entertainer, i.e. young women at bars who are paid to engage in conversation with men, light their cigarettes, sing karaoke, and sometimes dance – with a strict policy against men touching the hostesses or making sexual propositions. Popular hostesses often receive drinks, presents and social invitations from their favourite customers.

Joji Obara was born in 1952 to poor Zainichi Korean parents in Osaka. During his youth, Obara's father worked his way from scrap collector to immensely wealthy owner of a string of properties and pachinko parlors. Obara was educated at private Tokyo schools, and received daily tutoring in a variety of subjects. At age 15, he enrolled in a prestigious prep school affiliated with Keio University, virtually guaranteeing his acceptance into the latter institution upon graduation. Two years later, after his father's death in Hong Kong, Obara inherited property in Osaka and Tokyo. After traveling extensively and graduating from Keio University with degrees in politics and law, he became a naturalized Japanese citizen and legally changed his name. Obara invested heavily in real estate speculation, gaining assets estimated as much as $38 million. After losing his fortune and his firm in the 1990s recession, he was pursued by creditors, and reportedly used his business as a money laundering front for the yakuza syndicate Sumiyoshi-kai.