Japanese prosecutors extended the detention of former Nissan chairman Carlos Ghosn for a further 10 days on Friday, local media reported, as questions mounted about his treatment by the Japanese legal system.

Ghosn, one of the most charismatic and successful executives in the automobile industry, was arrested out of the blue Nov. 19 on charges of financial misconduct and has been held ever since at the Tokyo Detention Center. 

He has subsequently been ­dismissed by Nissan and Mitsubishi, where he was also ­chairman, but not by Renault, the French wing of the three-company alliance where he remains CEO.

Tokyo prosecutors on Friday successfully asked a judge for an extension of his detention until Dec. 10, broadcaster NHK reported, at which point they will either have to indict him, arrest him on a different charge or release him.

Japan’s newspapers have since carried extensive leaks about Ghosn’s alleged crimes, alleging that he underreported his income in securities filings and used company money to pay for the purchase and upkeep of luxury houses around the world.

They have also reported eagerly on his inflated salary, which was high by Japanese standards but not when compared with those of some top U.S. CEOs.

But if the Japanese media have at times seemed to assume Ghosn’s guilt, the media in France and elsewhere have taken a much more skeptical line, linking his arrest to his plan to push for a closer merger between Renault and Nissan and the opposition to that plan within the Japanese auto company.

Last Sunday, French Finance Minister Bruno Le Maire said his government and Renault had yet to see evidence to support Nissan’s allegations against Ghosn.

Questions have also mounted on social media in Japan, where widely shared blog posts and tweets have voiced unusually strong criticism of a legal system in which, experts say, prosecutors are powerful, conviction rates after indictment are above 99 percent, interrogations can stretch for 20 days without attorneys being present, visits by family members are restricted, and the presumption of innocence is less strong than in the United States or Europe.

Before his downfall, Ghosn was a star in the business world in Japan, and there was even a manga comic book on his life, although his salary attracted criticism. Even here, several commentators have cast Ghosn as a likely victim of politics within the Franco-Japanese automaker.

Nobuo Gohara, a lawyer and former prosecutor, says almost everyone in Japan who is arrested is treated as if they are guilty, including by the media. And conviction rates are so high, he added, that most people plead guilty once they have been indicted.

“In Japan, prosecutors are extremely powerful; such is the relationship between the court and the public prosecutors,” he told the Foreign Correspondents’ Club of Japan this week. 

“In cases such as this one, in cases where prosecutors themselves are involved in investigating, they almost always indict suspects,” he said. “The point of no return has been reached as far as the prosecutors are concerned. That leads to media coverage which seems to assume a suspect being guilty.”

Kana Sasakura, a law professor at Konan University in Kobe, said the situation was not unique to Ghosn but was a feature of a legal system that has been criticized for decades by foreign countries.

“Because it was a celebrity who was arrested, it is getting a lot of attention,” she said, noting the big difference is Japanese prosecutors can detain and interrogate people for much longer than in the West before bringing charges.

But she said an overhaul of the system was underway, with voice and video recording of interrogations allowed more frequently and the Bar Association working to make it easier for suspects to have attorneys present. “Momentum is building,” she said.

Ghosn was arrested along with former Nissan representative director Greg Kelly. 

His attorney told the Reuters news agency Thursday that Kelly denied having underreported Ghosn’s salary, maintaining that although Nissan had discussed deferring some payments to Ghosn until after he had left the company, no firm agreement had been reached or amount set, and that there was therefore nothing to hide.

Gohara, the former prosecutor, also questioned the basis of the case against Ghosn, calling the prosecutors’ work “haphazard” in a case with such serious economic and social ramifications.

Many commentators have also pointed out that top Japanese executives appear to have sometimes escaped with relatively lenient treatment by prosecutors after being accused of seemingly more-serious crimes.

Earlier this year, senior executives from two of Japan’s biggest contractors escaped indictment after confessing to bid-rigging an $80 billion maglev railway and cooperating with prosecutors, while charges were never brought against top Toshiba executives accused of financial fraud in 2016.

But prosecutors rejected the criticism in a news conference Thursday.

“We do not unnecessarily keep people in custody for a long time,” said Shin Kukimoto, the deputy head of the Tokyo prosecutor’s office. “I do not criticize other countries’ systems just because they are different.”