Former Instructor’s Secret Filming Habit Exposed After Over 100 Voyeuristic Incidents

Secretly filming over 100 times at an all-girls school

“I thought I could take them well because inside the school, people are less cautious than when walking outside,”

said the former teacher, who repeatedly committed secret filming over 100 times at the girls’ school where he worked, explaining his motive.

“The Katsushika Police Station of the Tokyo Metropolitan Police arrested Atsuto Sato (33), a full-time teacher at a private girls’ junior high school, on suspicion of providing sexual image records, by November 12, 2025. Between June 29 and July 5, 2025, he allegedly provided five images taken inside skirts at his workplace in three separate instances.

In July 2025, the Katsushika Police arrested another man for secretly filming at a train station. When that man’s smartphone was analyzed, it was revealed that he had received secretly filmed images from Sato. Sato admitted to the allegations and was subsequently dismissed from the girls’ school where he worked,” reported a journalist from a national newspaper’s social affairs desk.

On February 25, the second trial of Sato, charged with both filming sexual acts and providing sexual image records, was held at the Tokyo District Court, and the case was concluded that day.

The indictment read by the prosecution and the opening statement revealed the despicable acts of Sato, who could not stop secretly filming.

“The defendant began secretly filming no later than spring 2023, and by around November of that year, he was discovered filming high school girls’ underwear at a train station, prompting him to attend counseling. However, by summer 2024 at the latest, he began using a pen-type camera purchased for the purpose of secret filming to record videos of students’ underwear inside the girls’ school where he worked.”

Believing that inside the school, students would not be cautious about being filmed and he could film more effectively than at the station, he committed secret filming over 100 times before being arrested.

Met a like-minded companion on an online forum

Atsuto Sato explained the reason he started taking voyeuristic videos as follows:

“I was watching that kind of video on the internet and thought that maybe I could do it myself. And whenever I felt stressed, I started taking voyeuristic videos.”

However, as he continued the acts, his purpose seemed to change.

“The initial reason was, of course, to satisfy sexual desire. But at some point, the voyeurism itself became the goal — or rather, I started doing it to experience the thrill.”

As mentioned earlier, in this case, another man was caught in the act taking voyeuristic videos at a train station, and Atsuto Sato’s voyeuristic images were found on that man’s smartphone, which led to Sato’s arrest. What kind of relationship did he have with this man? In response to a prosecutor’s question, Sato stated the following:

“I met this man on an online forum. He called himself ‘Cobalt’ and liked to take voyeuristic videos of students at my school. As we continued exchanging messages, we began sending each other the voyeuristic images we had. I called myself ‘Hunter A,’ capturing videos of skirts taken inside the school and sent images without faces to ‘Cobalt.’”

“A state where I couldn’t control myself”

When the prosecutor asked how he felt about interacting with Cobalt, who was obsessed with students at the girls’ school where he worked, Sato replied, “Since I was also taking voyeuristic videos, there was a kind of twisted sense of camaraderie.”

He also revealed during their exchanges that he himself was the teacher at the girls’ school whom Cobalt was obsessed with. Naturally, Cobalt asked for information, but Sato testified, “I did tell him the names of some students who were filmed, but I certainly didn’t reveal their addresses.”

On this day, the closing arguments were delivered.

The prosecutor stated that Sato’s actions were extremely malicious, exploiting the trust of students for his own sexual desire, and added, “Out of a desire to be recognized by fellow voyeurs, he provided personal information and voyeuristic images of students he was supposed to protect, acting out of extremely selfish reasons with no room for leniency,” and sought a three-year prison sentence.

On the other hand, the defense argued that Sato, who was out on bail, has already begun treatment at a specialized clinic, and family supervision can be expected going forward, asserting that a suspended sentence would be appropriate.

Sato reflected on his arrest, saying he felt some relief at the time. When asked by his lawyer why, he answered:

“I was in a state where I couldn’t control myself, so this time I felt I absolutely had to stop.”

In his final statement, he said, “As a teacher and as a human being, I engaged in actions that were utterly improper. I will make absolutely sure not to repeat such behavior in the future.”

If Sato is able to stop his voyeuristic behavior following this arrest, it could prevent new victims. However, the anxiety of his former students about possibly having been filmed, and their anger over the fact that a teacher at their school took voyeuristic videos and provided them to others, will not disappear so easily.

The verdict is scheduled to be delivered on March 13.

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