Nearly a year after former Renault-Nissan CEO Carlos Ghosn made his stunning escape from Japan, smuggled in a musical-instrument box, a panel of lawyers working under the ambit of the United Nations issued a strong rebuke of Japanese officials, saying that they had arrested Ghosn arbitrarily and held him under abusive conditions.

The ruling came after months of investigation by the Working Group on Arbitrary Detention, a group of five experts which tries to determine whether U.N. members have violated international treaties they have signed.

In Ghosn’s case, the lawyers found, Japan most certainly did when they arrested Ghosn four times during 2018 and 2019, accusing him of underreporting about $88 million in earnings over nearly a decade, and using about $16 million in company funds for private spending—charges that Japan seemed willing to prove, even at the cost of violating human rights, according to the international lawyers.

“Mr Ghosn was subjected to unjustifiably prolonged detention in harsh conditions,” the 17-page finding says, adding that Japanese officials “gravely compromised” Ghosn’s right not to incriminate himself, and that he enjoyed little presumption of innocence—principles to which Japan has signed on in international treaties.

In the long-running drama around Ghosn’s legal woes, the panel’s findings seem almost small. After all, it is hard to top Ghosn’s escape in December 2019, under the noses of Japanese officials who had touted their arrest of a world-renowned auto executive as a major legal coup.

Yet one of Ghosn’s lawyers told Fortune on Monday that the experts’ findings could be crucial in ultimately winning his case, which continues in Ghosn’s absence. By showing that Ghosn had been forced to incriminate himself while in jail, the panel of lawyers were in effect throwing the government’s entire case in doubt.

“It will definitely weaken all the parts of the accusation based on the Japanese investments or procedures, because it does not comply with international treaties and human rights decisions,” François Zimeray, Ghosn’s lawyer in Paris, told Fortune. “Forced self-incrimination, plus other violates, effects the validity of the procedures.”

Exiled in Beirut

Hidden in a box, Ghosn was loaded on to private jet in Tokyo and spirited to luxurious exile in Beirut, where he has since holed up in his large mansion in the Lebanese capital; he has Brazilian, French and Lebanese citizenships. Less fortunate by far was Nissan executive Greg Kelly, arrested with Ghosn, who is now on trial in Tokyo, charged with concealing Ghosn’s earnings over several years. If convicted, Kelly could face up to 15 years in prison.

Zimeray—who is not involved in Kelly’s case—says the panel’s report on Monday brought deep relief to Ghosn, who felt a sense of validation about his “nightmare” at the hands of Japan’s legal system. “One could not find higher or more eloquent recognition,” he says of the report. “it is structured legally, and argued as it would have been in a judgment.” The lawyers, from Australia, Latvia, South Korea and Zambia, recommended that Japan compensate Ghosn, 66, for having been arrested four times.

Japan’s Foreign Ministry said in a statement on Monday that the report was “based on limited information and biased allegations,” and that “the opinion is totally unacceptable, and is not legally binding.”

Indeed, the panel has no judicial power. It exists simply as a form of moral check on whether countries are violating international rules. But even so, Zimeray is hoping that the report might persuade Japan to ease off its aggressive prosecution of cases; about 99% of trials in Japan end in convictions. “The Japanese are quite sensitive to the U.N., and this could definitely have an impact on the country,” Zimeray says.

That would be welcome news for Michael Taylor and his son Peter, who have languished in a county jail near Boston since May, awaiting their extradition to Japan where they are indicted for helping to mastermind Ghosn’s epic flight from Japan.

The older Taylor, a former Green Beret-turned private-security businessman, was hired by a Lebanese contact to get Ghosn out of Japan. He tapped his son Peter for help, and together they devised how to extract the multimillionaire from the grip of Japanese authorities.

The Taylors have not denied their roles in the extraordinary escape, whose details read like a Hollywood thriller. But they say it was not a crime under Japanese law to help Ghosn, since he was out on bail at the time.

“There is only one positive to this, which is that I helped save a man’s life,” Michael Taylor told the Wall Street Journal last week, from jail. “I wish I was never involved.”

With Japan's tough legal system outlined in Monday's report by the international lawyers, Taylor's wish could now be a lot stronger.