Chilling Crimes: Suspect Used Death Threats and Sleeping Drugs to Target Three Women

“I’ll kill you, I’ll kill you, I’ll kill you.”

A man who committed indecent acts on a train allegedly carried out the acts while threatening a high school girl with these words.

“On July 23, 2025, the Urayasu Police Station of the Chiba Prefectural Police arrested Yosuke Oka (45), a self-proclaimed company employee from Kashiwa City, Chiba Prefecture, on suspicion of non-consensual indecent assault. Oka is suspected of committing an indecent act by touching the body of high school student A (then 16) while she was commuting to school on a train in late May.

The incident came to light after A reported the assault to the police box in front of the station after getting off the train. Subsequently, Oka emerged as a suspect following an investigation using the station’s security cameras and other evidence. Oka reportedly denied the charges, stating, ‘I have absolutely no idea what you’re talking about.’” (National Newspaper Social Affairs Reporter)

Following his arrest, further charges were uncovered during the interrogation of Okada, leading to additional arrests. The aforementioned social affairs reporter continues:

“On September 25, the Shinjuku Police Station of the Metropolitan Police Department arrested Okada on suspicion of indecent assault. He is suspected of spiking the drink of Ms. B (then 23), whom he met on a dating app in early May, with a sleeping pill and committing indecent acts against her while she was unconscious.

When Ms. B regained consciousness and consulted the Metropolitan Police Department, traces of the sleeping pill were detected in her system, confirming she had been victimized. The series of crimes was captured on nearby security cameras. Defendant Oka partially denied the charges, stating, ‘I did not give her the sleeping pills in order to touch her body.’

Furthermore, in mid-July, he was arrested and indicted on additional charges of non-consensual indecent assault for groping Ms. C (then 20 years old) on a train.

In addition to this series of crimes, Defendant Oka has a prior conviction for violating the Public Nuisance Prevention Ordinance and for indecent assault, and he completed his sentence in December 2019.”

On February 16, 2026, the first hearing was held at the Chiba District Court for Defendant Oka, who is charged with three counts of non-consensual indecent assault. The indictment read by the prosecutor and the opening statement revealed the nature of Defendant Oka’s despicable crimes: he rendered women unable to resist through threats or sleeping pills before committing indecent acts.

After using a sleep aid to cloud her consciousness

“On a morning in mid-May 2025, the defendant was looking for a potential victim at a station on the JR Musashino Line. Upon seeing Ms. A board the train, he followed her inside. He then pressed himself against Ms. A from behind while the train was in motion and committed indecent acts, such as reaching inside her skirt.”

At that moment, Defendant Oka allegedly threatened Ms. A as described at the beginning, and continued as follows:

“If you make a scene, I’ll kill you. I have a knife.”

He met Ms. B around April through a dating app and began exchanging messages with her. It is said that the day of the incident was the first time the two had met in person.

“The defendant paid Ms. B, whom he had met through a dating app, 10,000 yen as a fee to have a meal together, and they visited a yakiniku restaurant in Shinjuku Ward. Then, while Ms. B was away from the table, he mixed a sleeping pill he had dissolved in a soy sauce dispenser he had brought with him into her drink and made her drink it. As Ms. B’s consciousness began to fade, he took her by the arm and led her into a private room at a nearby bar, where he committed indecent acts, including putting his hand inside her clothing.”

When he committed indecent acts against Ms. C, Defendant Oka also used threats to render her unable to resist.

“In mid-July, while the defendant was looking for a potential victim for indecent acts at a station on the JR Yamanote Line, he spotted Ms. C boarding the train. He then boarded the same car and pressed himself against her from behind. He threatened her with statements such as ‘I’ll kill you,’ and committed indecent acts, including reaching inside her clothing.”

Terrified, Ms. C reportedly got off the train once. When she reboarded the train through a different door, Defendant Oka persistently followed her.

“I don’t remember, or it’s unclear.”

“The defendant sat next to Mr. C, who was seated, and poked Mr. C in the side with his elbow. A passenger who could no longer bear to watch this spoke to Mr. C and pretended to start filming the defendant, at which point the defendant got off the train and fled.”

According to Mr. C’s written statement read aloud by the prosecutor, Mr. C had been a victim of sexual abuse as a child. He stated that being victimized by Defendant Oka brought back memories of that time, leaving him unable to speak up. He testified that since the incident, whenever he sees a man resembling Defendant Oka in build, he experiences flashbacks that cause his heart to race.

Finally, C expressed his anger as follows:

“After this incident, I began experiencing severe anxiety, so I’ve been attending a mental health clinic and have been prescribed medication to alleviate it. As for the perpetrator, I ask that he be given a severe punishment so that he remains in prison for as long as possible.”

Although Defendant Oka had previously served in the Ground Self-Defense Force, he was working at a restaurant at the time of his arrest. He stated in court that he is currently unemployed. He admitted to the charges by saying, “There is no mistake,” but clarified that this meant, “The person captured on the security camera is definitely me.” Defendant Oka, who stated that he had been prescribed sleeping pills at a hospital, made the following statement regarding the crimes themselves:

“Due to the effects of the sleep aids I was taking, I have no memory of the crimes or my memory is unclear in some parts.”

If he has no memory, there is a possibility he will not speak in court about the crimes he committed. Defendant Oka, who acted on his own desires to rob the female victims of their ability to resist and subjected them to the worst possible abuse. Will we ever hear words of apology from him?

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