Home » Brutal Cases » Nevada-tan (Natsumi Tsuji), killed her 12-years-old classmate Satomi Mitarai

Nevada-tan (Natsumi Tsuji), killed her 12-years-old classmate Satomi Mitarai

With intelligence considered genius, Nevada-tan was an 11-year-old Japanese girl who killed her friend at school in a cruel way.

Nevada-tan is the nickname given to an 11-year-old girl who murdered her 12-year-old classmate. The crime occurred on June 1, 2004, in the city of Sasebo, located in Nagasaki Prefecture, Japan.

The real name of the criminal is Natsumi Tsuji, which at the beginning of the case remained under secrecy due to a Japanese law that does not allow the release of the names of underage offenders. However, it accidentally came to leak on the Internet.

Moreover, this case can also be identified by the name of Sasebo slashing, and has even become a meme on the Internet, due to people who sympathize with this type of crime — yes, it exists, and it usually occurs among children and young people who have identified with the killer.

What has always intrigued since the beginning of this story is that the two girls were very good friends, but then why would one go so far as to murder the other? What would motivate a child to commit such a cruel crime?

Nevada-tan under the left arrow, wearing the sweatshirt that gave origin to her nickname; and Satomi Mitarai under the right arrow.

Nevada-tan (Natsumi Tsuji) murdered her classmate Satomi Mitarai

That day, Nevada-tan was bringing a box cutter to school. At lunchtime she persuaded Satomi Mitarai to enter a classroom which was empty, and then closed the curtains.

First she said she wanted to show her a new game. Then she made Satomi sit down on a chair and took off her glasses. She told her that she was going to die, but Satomi did not run away. After all, she believed it was a game.

Natsumi said she couldn’t look, so she covered her friend’s eyes with one of her hands and, with the other, pulled out the box cutter she had brought to school and cut deeply into the victim’s neck.

Now with her throat slit, Satomi could not scream for help and was unable to defend herself. Natsumi continued the attack, this time cutting her wrist. The victim fell to the classroom floor, agonizing in total silence. Nevada-tan stood watching her friend bleed to death.

After that, Nevada-tan left the classroom where the murder took place and without showing any remorse, she walked to the classroom where the teacher was, walking through the halls of the school covered in blood.

The teacher, who had already noticed that the two girls were missing, panicked. She thought Nevada-tan had accidentally cut herself, until the girl said “this is not my blood”. She ran off to find Satomi. Nevada-tan followed behind her, crying and repeating, “I did something wrong”.

The school called an ambulance, the police, and the victim’s parents with the warning that their daughter was “hurt”, but in fact she was already dead.

When the ambulance arrived, Satomi Mitarai had already died from the high amount of blood lost, her parents arrived soon after. Nevada-tan repeatedly apologized for what she had done.

When the police arrived, Natsumi confessed to the crime, and then said she was planning the act for four days. At the police station, she showed some remorse: “I did something wrong, didn’t I? I’m sorry, I’m really sorry,” she spoke while crying.

Satomi Mitarai, the victim.

Friendship between Nevada-tan and Satomi Mitarai

The two girls were close friends. They were often seen walking together and, according to reports from colleagues, there appeared to be nothing wrong between them, even in the days leading up to the crime.

Nevada-tan had an intelligence considered genius, her grades at school were great, but she also had an obsession with horror movies and seemed to have difficulty inferring what was real from what was fantasy.

Reasons for the crime

Due to her mother’s restrictions on other tasks, Natsumi began to use more the computer, where she became a fan of anime and got to know the Japanese movie Battle Royale. The girl quickly identified with the scenes of violence in it.

Battle Royale is a film about a futuristic society in which 42 students are sent to a desert island where they have to survive by killing each other.

At that time, she had the idea of creating a website with horror animations.

Subsequently, Satomi and Nevada-tan had an argument. As a form of revenge, Satomi posted on her friend’s website saying that she was “fat” and “pretentious”. Natsumi became very angry and required her friend to apologize.

Satomi refused to apologize, and this increased Nevada-tan’s anger until it resulted in the murder of her friend.

Finally, we can conclude that the murder occurred for futile reasons. Nevada-tan already had traits of a problematic person, and this was confirmed in the reformatory where she stayed in the following years.


On September 15, 2004, the Japanese court decided to send the girl to a reformatory because of the seriousness of the crime. She was sent to a reformatory where she remained under observation for the next 9 years. The idea was a lesser sentence, but in the beginning Nevada-tan didn’t demonstrate evoulation.

After two years in reform school, in September 2006, the court decided to extend this period for another two years. They wanted to continue her psychological evaluation, because from her strange behavior, they believed that the girl could still present a danger to society.

On May 29, 2008, she was granted house arrest. The Japanese court said she had developed the necessary skills to interact with other people and the authorities said they were not looking for an additional sentence.

In 2013, at the age of 20, she was released by the courts, with her sentence fully served. Her family moved to an unknown location.

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