Shocking Truth Behind the Sekisui House Case Revealed in Mastermind Inmate’s Letter

Where did the 5.5 billion yen go?

“(Excerpt omitted) To Mr. Isao Mori,
I am Kaminskas, who was made out to be the mastermind of the Sekisui land fraud case. I believe you are quite knowledgeable about this incident. Shortly after it became a case, you published ‘Jimen-shi’.”

This is how the letter began. It was sent to nonfiction writer Isao Mori in April 2024.

The sender was one of those infamous land swindlers who defrauded one of Japan’s leading homebuilders of 5.5 billion yen and even became the model for a hit drama—Kaminskas Misao (66), who was arrested in January 2019 on charges including fraud as the alleged mastermind of the “Sekisui House case,” centered around the inn “Umikikan” in Gotanda, Tokyo, and was sentenced to 11 years in prison (hereafter, “Kaminskas”).

In the letter, Kaminskas posed the following question to Mori, the author of “Jimen-shi: The Dark Fraud Group That Sells Other People’s Land,” which later became the basis for a Netflix drama released in July 2024:

“What do you think of me, Mr. Mori? I’ll be clear—I am innocent.”

Kaminskas is considered a key figure and the model for “Takumi Tsujimoto,” played by Go Ayano in the drama. How did Mori interpret a letter from such a man?

“Kaminskas led the negotiations with Sekisui House and was even present at the property viewing of Umikikan. There’s no way he could be innocent. I initially thought it was just a grudge-filled rant.”

However, as Mori continued reading, his impression began to change.

“The ones who actually planned the fraud were people like Mike Uchida, Yoshio Doi, and Fumiaki Kitada. I regarded these three as the real masterminds. They were major players in the land acquisition underworld, involved in numerous shady deals. Compared to them, Kaminskas seemed more like a supporting figure.

Yet, at some point, he ended up being reported as the mastermind of the case. I thought his letter might hold the key to understanding the full picture of the complex land swindler group and the Sekisui House case.”

As if responding to Mori’s thoughts, Kaminskas wrote the following in his letter:

“I was deceived and manipulated by the land swindler group. Originally, the property itself was one I had been tricked into through Yokozawa (alias; real name given in the letter) from Emile (Holdings), but Yokozawa was never arrested, and no interrogation records have surfaced.”

“Yokozawa of Emile” is said to be the man who drew Kaminskas into the fraud group. In the letter, Kaminskas claims that it was Yokozawa—who was the original broker of the Umikikan property (a broker directly entrusted by the landowner to find a buyer)—who brought him the deal.

He also wrote that he did not know the supposed landowner introduced by Yokozawa was an impostor. In other words, he claims, “I was deceived by Yokozawa and merely got caught up in the incident.”

Regardless of the truth of Kaminskas’s claims, there is no doubt that Yokozawa is a key figure in unraveling the case. However, Yokozawa was never arrested. A senior police official involved in the investigation said:

“I recall Yokozawa’s name coming up early in the investigation, but the Sekisui House case had so many targets that he seemed to disappear midway through. Still, if you ask whether there were any oversights in the investigation, it’s hard to say definitively. We cannot rule out the possibility that Yokozawa was deeply involved.”

Yokozawa has also caused a stir in other cases. In 2024, his name was repeatedly reported as the ringleader of an M&A fraud group. He allegedly targeted struggling small and medium-sized companies with M&A deals, stripped them of their remaining assets, and then disappeared—carrying out one malicious scheme after another, even leading to the formation of a victims’ association.

“Yokozawa was involved in more than 30 such M&A cases. Some victims have filed criminal complaints with the police. He reportedly spent tens of millions of yen annually at hostess clubs in Mito City, Ibaraki Prefecture, where he was based,” said Mori.

Was the money obtained from the Sekisui House case the source of his lavish lifestyle? The key figure in the case remains missing to this day.

Who is telling the truth? Where did the defrauded 5.5 billion yen go?

One of the biggest mysteries left in the case is the whereabouts of the 5.5 billion yen that was swindled. In his letters, Kaminskas repeatedly insists:

“The only money I received was 100 million yen as a referral fee at the time of the provisional contract.”

Mori is skeptical of this claim.

“It’s hard to believe that Kaminskas, who played a central role in executing the fraud, received less than 2% of the total. This is likely a lie.”

Around the time Sekisui House was entering into a provisional sales contract with the impersonated landowner, Kaminskas purchased two units in a luxury high-rise condominium.

In Mori’s latest book “Jimen-shi vs. Jimen-shi,” a person who claims to have bought those units from Kaminskas gave the following account:

“Koyama (Kaminskas’s former surname) was living very lavishly at the time. You can’t live like that on just 100 million yen. At night, he would splurge in Asakusa, lending tens of millions—30 or 50 million yen at a time—to younger associates. He even had six mistresses. Back then, he probably had around 700 to 800 million yen.”

The account of another key figure also directly contradicts Kaminskas’s claims. Mori continues:

“In August 2025, a letter from Fumiaki Kitada published by writer Momoko Kawai in Shukan Post stated: ‘Koyama 1 billion, Doi and Kitada 1 billion each, Mike about 300 million.’

When I relayed this to Kaminskas, he responded:

‘The distribution of money that Kitada mentions is incorrect. I think Doi probably lied to Kitada. The actual distribution was likely 2 billion yen for Doi, 1 billion yen for Kitada, 300 million yen for Uchida, and the rest divided among others.’”

Just like in a drama, the swindlers appear to be deceiving one another. The Sekisui House case remains shrouded in numerous mysteries as it approaches the 10-year mark since it first came to light.

From “FRIDAY”, May 24, 2024 issue