Even After His Arrest for Stalking, He Sent Vengeful Emails to the Victim… The Abnormal Obsession of a 52-Year-Old Man Revealed by a Woman in Her 20s During Trial

“You really did it, didn’t you?”

The first hearing for defendant Mitsuo Osaka (52 at the time of arrest), who is charged with violating the Act on the Regulation of Stalking and Related Acts for repeatedly sending emails to the female victim out of resentment over his arrest for stalking, was held on September 16 at the Tokyo District Court.

“Defendant Osaka was arrested in May of this year on suspicion of violating the Anti-Stalking Act for sending emails to Ms. A, a woman in her 20s who was a former colleague at a restaurant, containing romantic overtures and hints about his own suicide. He was fined 300,000 yen and also received a restraining order under the Anti-Stalking Act.

Upon learning that his arrest had been triggered by Ms. A’s consultation with the police, Defendant Osaka was re-arrested for sending her messages and images expressing resentment over his arrest, including remarks such as, ‘You did it, didn’t you?’ and ‘I’ll spend what little life I have left eating cold meals behind bars,’” said a reporter from the crime desk of a national newspaper.

Wearing a gray sweatsuit, Defendant Osaka entered the courtroom, hunching her slender frame. Her hair, long enough to cover her ears, was parted in the center and highlighted with gold streaks. Although a mask covered half her face, the lifeless eyes peering out from beneath it seemed devoid of emotion.

When the hearing began and Osaka was ushered to the witness stand, she stood there quietly, without making a sound. During the preliminary questioning, she answered her name and address in a soft voice; when asked about her occupation, she replied, “I am not currently employed,” indicating she was unemployed. Regarding the charges against her, she admitted , “That is correct.”

The opening statement read by the prosecution revealed the intense delusions underlying Defendant Osaka’s obsession.

After graduating from high school, the defendant, Osaka, became a chef and worked at a restaurant. In ’24, Ms. A (then 20 years old) began working part-time at the same restaurant, and the two became coworkers. Since they shared a common interest in music and liked the same bands, the defendant, Osaka, and Ms. A began going out to eat and to concerts together.

For Ms. A, the defendant was nothing more than a coworker with whom she shared a common interest, but the defendant—despite the nearly 30-year age difference—came to believe that she and Ms. A were in a romantic relationship.

However, when Ms. A began seeing someone else, the defendant’s distorted feelings began to spiral out of control.

“I wanted her to regret getting involved with my boyfriend.”

In March of ’26, Ms. A began dating another man. She told the defendant, Osaka, “I’m seeing someone else, so I can’t go out to dinner or to concerts with you anymore.”

Although Osaka was not in a romantic relationship with Ms. A, he demanded that she block contact from her boyfriend. He then began exhibiting extremely controlling behavior, such as demanding to see her smartphone to confirm she had blocked him. Furthermore, after Osaka made suicidal remarks, Ms. A consulted the police, leading to his arrest.

During questioning about her motive for the crime, Defendant Osaka stated,

“I wanted her (Ms. A) to know that it was her fault I was going to die. She chose her boyfriend over my life. I wanted her to regret having anything to do with him,”

Regarding the fact that she committed the crime again despite having been subject to a restraining order after her previous arrest,

“I had no job, couldn’t go back to my parents’ house, and ran out of money. All I could think about was dying. I started to blame the acquaintance who introduced the victim (Ms. A) to her boyfriend,”

It appears her paranoia had escalated to the point where she was directing her anger toward people other than Ms. A. From Ms. A’s perspective, she must have hoped the situation would calm down after the defendant, Osaka, was arrested and served with a restraining order. However, the defendant sent an email expressing resentment over her arrest. The fear Ms. A felt upon receiving it is immeasurable.

“On September 30, the Mito District Court sentenced a man charged with murder and violation of the Stalking Regulation Act for killing his ex-girlfriend, a nail technician, at an apartment in Mito City, Ibaraki Prefecture, in December 2025, to a 20-year prison sentence on September 30.

“The man realized his own psychological instability and tried to seek treatment at a psychiatric hospital. However, because he could not secure an appointment, he was unable to receive treatment, which led to the worst possible outcome. Medical support alone has its limits. The reality is that, despite the rise in stalking crimes, countermeasures are lagging behind,” said a judicial affairs reporter for a national newspaper.

What will defendant Osaka say during the upcoming trial?