Christopher “Moot” Poole, 4chan’s founder, announced this week that he’s sold his website to Hiroyuki Nishimura, creator of 2channel (2chan)—4chan’s inspiration and template.

If you don’t know 4chan, the message board created in 2003, you don’t know one of the darker sides of the web. Don’t feel compelled to go exploring.

4chan has been called a “witty, inventive, bilious, (anonymous) and gleefully misogynistic message board” that created the existence of the net troll, but has also spawned social justice movements, Anonymous, and rebellion against Scientology.

It is, too, a place where killers post photos of their battered girlfriends, cyber trolls gang up on 11-year-old girls, and members root on murders or suicides.

“None of us would be using 4chan today—or potentially any anonymous image board—if it weren’t for him,” Poole wrote of Nishimura. “He is one of few individuals with a deep understanding of what it means to provide a digital home for tens of millions of people for more than a decade. There is nobody more qualified than Hiroyuki to lead 4chan, and I can’t think of a person better suited for the task.”

Everything has come full circle.

But is that a good thing?

Who is Hiroyuki Nishimura? Why did he buy the website? How much did he pay? And what will he do with it?

The new owner of 4chan has a mixed reputation in Japan: an entrepreneur, a free speech activist, a celebrity, and a genius. He does interviews in a magazine called Weekly Playboy—including conversations with Takafumi Horie, the former CEO of Livedoor. Horie was once the poster-boy of Japan’s net bubble—until he was nabbed for securities fraud, and later convicted.

Nishimura is a regular celebrity guest on Japanese television. He’s even known by the friendlier “Hiroyuki” rather than by his family name, which is unusual in Japan.

But an official at the National Police Agency speaking on background to The Daily Beast said that things like 2chan and 4chan could be wonderful tools for organized crime—if they fell into the wrong hands. He mentioned the Yubitoma case as an example.

In 2006, an associate of the Yamaguchi-gumi Kodo-kai gang effectively took over Japan’s version of classmates.com called Yubitoma, although this only became public knowledge in 2007 when the Yomiuri Shimbun—Japan’s largest newspaper—reported the story.

Over 3.5 million people registered for accounts on Yubitoma.

“Here you had a giant social network run by private individuals. And then the mob had it,” said the official.

Now, this National Police Agency source thinks 4chan, like 2chan before it, could become an even bigger tool for mob activity.

“People post things on the web that they later regret. It’s a treasure trove for blackmail—especially if you were to manage the site,” said the NPA source.

There’s no direct evidence that Nishimura has ties to anti-social forces, although—according to reports in the Asahi, Yomiuri, and other newspapers—authorities did suspect him of abetting them at one time.

But it’s no secret that the Tokyo Metropolitan Police Department isn’t a fan of Nishimura—and its officers are quick to go on background to speak about him to Japanese press. (In Japan, the civil servants law and the State Secrets Act have severe penalties for public servants speaking freely to the press, so on-record sources rarely appear in print.)

This could be a reaction from a police force that doesn’t yet seem to particularly adept at handling cyber crime—and sometimes gets taken for a ride by the kind of trolls and hackers that love to play on the cyber jungle gym that is 2chan.

Or it could be because both 2chan and 4chan have the same issues with seriously problematic, sometimes illegal content. 2chan has served as a platform for a number of grisly crimes—including disseminating detailed information for using hydrogen sulfide in group suicides.

In May 2000, a 17-year-old boy who called himself Neomugicha (“Neo-Barley Tea") posted a warning message on 2chan an hour before hijacking a bus in Fukuoka and killing one passenger. He was egged on by other 2chan users who, before the attack, didn’t take him seriously.

A copycat who called himself Neomugishu (“Neo-Barley Wine”) was later arrested after he boasted of a planned terrorist attack on a railway company.

A 16-year-old student in Nagasaki was arrested for murder after posts on 2chan hinted she had killed and decapitated a 15-year-old classmate.

When people plan to do or have done horrible things in Japan, 2chan is sometimes where they earn their 15 minutes of infamy. Hiroyuki was famously—and successfully—sued for defamation involving posts on 2chan. Years after rulings that allegedly ordered him to pay out over a half-million dollars, he still hadn’t handed over the cash by 2008. In an interview with Shukan Post, he even boasts of ignoring the lawsuits and not paying compensation.

“Yes, that’s correct. I’ve received more than 100 lawsuits so far. The reason why I don’t pay compensation is that I think I am not responsible for what others post,” he said. “If I were posting death threats or whatever, then I must pay. But I’m just a manager of 2ch. I don’t feel guilty at all.”

Japan’s Business Law Journal and Cyzo magazine have both dedicated coverage to how difficult it is to sue Nishimura and get him to pay up.

When a law office in Niigata actually succeeded in making the website pay damages, they announced their victory on their website. In Japan, this was reported as a major news story by four major newspapers in April 2010.

“It’s very rare for someone to have collected a lump sum compensation from (Nishimura). I will continue to fight for the rights of those who suffer from (what is written on) 2chan and other bulletin boards,” said Yutaka Saito, the lawyer who won the case. “Most just cry themselves to sleep.”

2chan had received 5,223 requests from police to remove illegal information by May 2012, police sources told Japanese paper Asahi Shimbun. Most of the posts were about drug use. Almost all of them—5,068—were left untouched.

Nishimura has been adamant that there is no moral or legal obligation to remove anything from the website.

“As the manager of the site, don’t you worry that you are going to pull the trigger in someone’s suicide?” he was asked in a 2003 interview with Asahi.

Nishimura refused to directly answer the question, but said that there were often just as many posts discouraging people from killing themselves—and that people who want to die should have access to that information, too.

On Dec. 16, 2011, the Weekly Asahi ran an article with the headline, “Tokyo Police Plotting A Campaign To Eradicate 2chan.” The story referenced the newly passed organized crime exclusionary ordinances, which were supposed to put the yakuza out of business—and indicated that going after 2chan would be an extension of that campaign.

Over a year later, on Dec. 21, 2012, the police filed charges against Nishimura on suspicion he “abetted” drug dealing.

The cybercrime unit of the Metropolitan Police Department alleged that allowing posts about trade in amphetamines and other drugs to remain on the board made him an accomplice. The charges were immediately controversial and even drew international attention. U.S. tech website TechDirt, for one, took a strong stand against it.

“So charges are being brought against the guy who simply founded the site that someone else may have once used to talk about something illegal, even though he sold the site three years ago and the statute of limitations has expired,” TechDirt’s Timothy Geigner wrote.

But it wasn’t that simple.

In 2009, Nishimura wrote on his blog he sold 2chan to the Singapore-based company Packet Monster and told the public he no longer had a hand in its management. But according to reports in the Yomiuri newspaper, when police raided his home and scanned his server, they found that he was still receiving advertising money and revenue.

Packet Monster, the police found, was a “paper company”—and Nishimura was the still effectively the manager of the website. Tokyo Police were also incensed that the company had shown little effort in removing damaging, illegal, or defamatory information going back to 2006.

In fact, Nishimura was said to have ignored hundreds of police emails requesting that posts related to the illegal drug trade, according to Jiji Press. The correspondences were sent from the National Police Agency, the Metropolitan Police Department Cybercrimes unit, prefectural police departments, and the Internet Hotline Center, which works with the police in cutting down and dealing with illegal activities on the web.

Most of the messages had already been opened, police found.

Nishimura had said on his blog, however, that he had received only two e-mail messages from police requesting him to delete online posts containing harmful or illegal information.

The prosecutors eventually decided not to indict him on March 19, 2013. They did not disclose a reason behind their decision.

In August 2013, Nishimura allegedly paid 30 million yen in tax penalties for failing to declare around 100 million yen of Packet Monster-related income to the Tokyo Regional Tax Authority between 2009 and 2012.

So does Nishimura still run 2chan? No one seems to know.

Why pretend not to be running the company if he actually is? That’s something that still intrigues Japanese law enforcement. According to the Japanese magazine FACTA, there is now a war waging behind the scenes at 2chan as to whom really controls it—Nishimura or the U.S.-based Jim Watkins, who overtook the domain in 2014.

On Wednesday, Hiroyuki published a self-introduction to 4chan users in English on his own website. The post was allegedly edited by Poole. It tells the story of his life and work in slightly glorified terms. In it, he talks about his business history and his relationship with Moot, before ending with his thoughts about the future of his most recent purchase.

“And yesterday, moot announced that I will take his place as the owner and administrator of 4chan. So my career has taken me ‘full circle,’ and moved back to the United States again, as it began all those years ago at the University of Central Arkansas in some 16 years ago,” he wrote. “With all that said, my comment to 4chan users is: ‘I am proud to be working together and a member of the 4chan community, which has been dedicated to the Internet meme industry and anonymous history for a long time.’

“Let’s build something great together, shall we?”