The Mystery Box
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The Mystery Box

Murder in Shibuya: Who killed Yasuko Watanabe?

The murder of the Japanese office lady who moonlighted as a prostitute

Yasuko Watanabe / Source: South China Morning Post

Fated Beginnings

Born in 1957 in a well-off Japanese neighborhood, Yasuko Watanabe would go on to major at Keio University. After graduating from one of the most elite universities with a degree in economics, Watanabe joined Tokyo Electric Power Company (TEPCO). Here Watanabe became one of the few women working at the TEPCO earning almost $100,000 a year.

Watanabe spent much of her time aiming to support her mother and sister after her father had perished, so she did not have many close relations that would give insight into her personal life.

However, in 1978, her father who she adored passed away. This had reportedly caused her to become depressed and lose much of her weight.

This sudden loss of her father may have been what caused her to seek other forms of comfort such as prostitution.

Prostitution and Crime

Leading a second life as a prostitute, Watanabe would clock out of work in the Shinbashi district, then walk to the train station. Getting off at Shibuya station she would prepare to do her second job.

Walking over to the Dogenzaka Jizo statue in Maruyama-cho, she would give a small prayer before starting to call out to men who walked by.

Dogenzaka Jizo / Source: Edopedia (

Aiming to get four clients per day, she would record each client meticulously in a red notebook she carried with her. On the day her body was found, there were 88 recorded encounters in this notebook.

It was during these encounters she met Nepali immigrant, Govinda Mainali.

Aspiring to better his wife and children’s lives back in Nepal, Mainali arrived in Japan in 1994 on a three-month tourist visa. During this time he tried to learn Japanese to be a tourist guide back in Nepal.

However, he overstayed his visa and became an illegal immigrant working at an Indian restaurant. Even still, he sent money back to his family consistently. He had accrued enough money where he was able to start building a house in Katmandu, the capital of Nepal.

During this time, Mainali met Watanabe and had sexual encounters on at least three separate occasions.

The Deadly Meeting and Discovery

On the day of her death, March 8th, 1997, Watanabe continued her usual routine of following her self-imposed quota of meeting four men a day.

Allegedly on this day, Watanabe called out to a man in a black and white jumper. Shortly after Watanabe entered the deserted apartment next to Mainali’s residence. This would be the last sighting of Watanabe until her body’s discovery.

11 days after Watanabe was killed, her body was discovered in that same apartment. Several Nepalese immigrants lived in this room before it went vacant in August 1996. During the investigation, it was found that beyond being murdered, money was taken from Watanabe’s purse.

Building Watanabe was murdered in / Source: Chinobouken

Shortly after the discovery of the murder, Mainali willingly went to the police while they were questioning the locals. Mainali claimed he did not do it, but police arrested him as they were suspicious of him.

While he was in custody, Mainali was charged with the robbery and murder of Watanabe. The evidence against Mainali was weak, but due to Mainali initially claiming he did not know Watanabe he was looked at more suspiciously.

Eventually, Mainali did admit to knowing and having sex with Watanabe. Even still, a lower court claimed there was not enough evidence to charge Mainali with the murder and robbery of Watanabe and he was released.

Prosecutors did not let up and instead re-arrested Mainali for overstaying his visa which allowed police to gather more evidence. With that, the evidence against him was growing. A condom full of Mainali’s sperm was found in the toilet of the apartment and his pubic hair was located in the apartment as well. According to Mainali he last had sex with Watanabe at the end of February and he did not see her on the day of her death.

With that, Mainli and his lawyers appealed his second arrest.

During the second investigation, it was revealed that Watanabe met another client that evening and the door was wide open when her body was discovered. In addition, Mainali’s lawyers conducted a test showing his sperm was old and there was an unidentified pubic hair on Watanabe that was not admitted to evidence. Beyond that, there were additional condoms not shown to the court.

Most notably, however, was the fact that Watanabe had saliva on her breast that came from a perpetrator with type O blood. Mainali’s blood type is B.

However, there is nothing more dangerous than a detective with conviction. The detectives on the case were set on Mainali being the suspect and they began the interrogation.

Interrogation, Alibis, Trial, and Punishment

At the time, Japan did not have many interpreters available. In this case, there was no available Nepali interpreter, so Mainali had to communicate with a police interpreter who speaks Hindi.

Mainali, his friends, and his roommates were all interrogated by the police. Some of his acquaintances were also illegal immigrants and were pressured into this interrogation.

In one case, Mainali’s roommate told police that Mainali came across money after Watanbe’s death and was able to pay back a loan of around $1,500 which would have been hard for Mainali at the time. Shortly after this confession, the roommate was deported.

Another roommate was interrogated but did not give much information. However, Mainali and his friends all claim they were beaten, attacked, and abused during their interrogation, and Mainali’s lawyers claim that most, if not all of the testimonies provided were gained by suspects under duress.

In addition, it would have been near impossible for Mainali to commit the crime as he was at work until 10 PM. Even if he were to rush to where Watanabe frequently looked for clients, he would not have arrived until 12 AM. Watanabe’s last known appearance was around 11:45 PM.

Following that, the building Watanabe was found in was next door to Mainali’s apartment. Even the most impassioned murderer would not keep the body that close to their own home for 11 days.

Mainali’s apartment / Source: Chinobouken

Ultimately, Mainali was fully charged with the murder of Watanabe and sentenced to prison where he spent most of his time in solitary-confinement.


However, Mainali and his lawyers consistently fought this charge and were eventually given another hearing. Finally, able to get their evidence admitted, 15 years later Mainali was released on the grounds of his DNA not matching the suspects.

Govinda upon his return to Nepal / Source: South China Morning Post

The Mysterious Killer

With 15 years passed, the true killer remains unfound. It seems unlikely that the true killer will be found either as the detectives on the case were so focused on charging Mainali, much evidence was ignored.

It would make sense for her killer to be the last client she saw that night, but as it was dark and much of the evidence was discarded. It would be hard to ever find her killer.

Even if the case were to be re-investigated, at the time of Watanabe’s death, the statute of limitations was 15 years. Because of this, even if the killer were to admit to his crimes he would not be able to be charged.



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