He Seemed Harmless—Then He Slipped Sleeping Pills into Her Soy Sauce

“I don’t remember clearly.”

The man, who looked frightened as camera flashes burst toward him the moment he glanced up—

On September 25, the man who appeared from the Shinjuku Police Station of the Tokyo Metropolitan Police for transfer to prosecutors was Yosuke Oka (45), an unemployed resident of Kashiwa City, Chiba Prefecture. He was arrested on suspicion of giving a woman a drink laced with sleeping pills to render her semi-conscious and attempting to commit an indecent act.

“According to investigators, in May of this year, Oka met a woman in her 20s through a matching app and invited her to a restaurant in Shinjuku, Tokyo, where he carried out the act. He reportedly brought sleeping pills in capsule form hidden inside a soy sauce dispenser and mixed them into the woman’s drink when she left her seat. The restaurant’s security cameras captured the scene. When questioned, Oka told police, ‘I didn’t give her the sleeping pills to touch her body. It’s true that I touched her, but my memory is somewhat vague, and I don’t remember clearly,’ partially denying the charges,” said a reporter from a national newspaper’s social affairs section.

Crimes involving administering sleeping pills to incapacitate victims and then committing assaults have long been known and still occur frequently.

In a case reported in May this year, a former staff member of Mukogawa Women’s University allegedly drugged drinks with sleeping pills and sexually assaulted several men aged 18 to 25 he met through dating apps between September 2022 and June 2024.

The Osaka District Prosecutors Office indicted the man for non-consensual intercourse between November 12, 2024, and January 31, 2025.

On September 24, another case surfaced in Okayama Prefecture: a man running a guesthouse was sentenced to 26 years in prison (prosecutors had sought 28) for giving alcohol laced with sleeping pills to ten female guests between September 2018 and June 2022, sexually assaulting them, and secretly recording them with cameras installed in the changing room of the bathroom.

There have also been numerous cases where sleeping pills were used for theft-related crimes.

The arrest rate is definitely increasing

“In April this year, at a karaoke bar in Kashima City, Ibaraki Prefecture, two women in their twenties were arrested in September for giving a 44-year-old man a drink laced with sleeping pills, putting him into a coma-like state, and stealing 150,000 yen in cash and his bank card. The act was captured on security camera footage, which led to their arrest,” said the aforementioned reporter.

Even just looking at cases that occurred this year, there are numerous incidents where suspects met their victims through dating apps, gave them drinks containing sleeping pills at bars or karaoke establishments, and then carried out their crimes. Many of these offenses took place indoors, and footage from security cameras often served as decisive evidence leading to arrests.

So why do these crimes continue to persist despite such measures? Crime journalist Taihei Ogawa explains:

“The victims are individuals with whom the perpetrators cannot achieve their goals through mutual consent. They render their targets incapable of resistance to satisfy their own desires — but at the same time, they don’t want to be found out. It’s one of the most despicable forms of crime, born from that contradiction.

Moreover, sleeping pills are easy to obtain, which makes it a crime people can commit with little hesitation. As a result, the number of such cases hasn’t decreased. While it’s now common practice for restaurants and karaoke bars to install security cameras, few openly advertise themselves as monitored by security cameras.

Some customers feel uncomfortable going to places that clearly display cameras, so many establishments install discreet surveillance cameras that are hard to notice. Customers may not realize they’re being filmed, but when crimes occur, that hidden footage is often submitted to the police and becomes crucial evidence. As a result, the arrest rate has definitely increased.”

Returning to the beginning of the story— Suspect Yosuke Oka, determined not to be photographed, kept his head down and hurried past the reporters, doing everything he could to keep his face from being captured on camera.