Defense lawyers started picking holes in testimony provided by a key witness in a trial to unravel the tangled finances of Carlos Ghosn, the former chairman of Nissan Motor Co. who fled Japan in dramatic fashion in late 2019.

With Ghosn out of the picture, his associate, Greg Kelly, 64, a former Nissan representative director, and the company itself are the only defendants appearing in court.

Defense lawyers on Dec. 8 ended their questioning of Toshiaki Onuma, who served as the head of the secretary’s office at Nissan and is the first person to provide testimony after entering a plea bargain arrangement with prosecutors.

Kelly was indicted on charges of violating the Financial Instruments and Exchange Law for not including Ghosn’s remuneration on Nissan’s annual financial reports for the period between fiscal years 2010 and 2017.

The total amount that went unreported came out to about 9.1 billion yen ($87 million). The money was to have been paid to Ghosn after he left the company and was part of the 17 billion yen or so in remuneration from Nissan for that period.

Onuma, 61, appeared on 11 occasions to respond to questions from prosecutors and later appeared nine times to be questioned by defense lawyers.

A key focus for the defense team concerned documents that Onuma touched upon in response to questions by prosecutors. The documents listed the total amount of unpaid remuneration to Ghosn with the promise to pay him the balance after he left Nissan. The remuneration was to be paid to Ghosn in his designated position of company adviser after he retired.

Onuma said the documents were compiled at the behest of Ghosn, adding that he showed them to Kelly after Ghosn signed the papers.

To undermine Onuma’s credibility, defense lawyers pointed to differences in what he said in court and the responses he gave prosecutors during the investigation phase.

Defense lawyers argued that Onuma said during the investigation that he showed a draft of the document to Kelly and no mention was made of showing Kelly the signed version.

Onuma responded that he told investigators he showed Kelly the final version rather than a document that was still in the process of being drawn up. But he could not recall if he told investigators about the signature.

The documents were created in 2011 and 2013 for Ghosn’s remuneration between fiscal years 2009 and 2012. But the charge against Kelly is for not reporting Ghosn’s remuneration up until fiscal 2017.

Defense lawyers asked Onuma if an agreement had been reached with Ghosn for remuneration after fiscal 2012.

“There was no discussion with Ghosn about creating a new document,” Onuma replied.

Defense lawyers also asked Onuma whether the document signed by him and Ghosn would be legally binding on Nissan.

“The document by itself was no guarantee that Nissan had to appoint Ghosn as an adviser,” he responded.

Defense lawyers also asked Onuma if he feared prosecutors might break the plea-bargaining agreement if his testimony in court differed from what he told investigators. 

But Onuma said he never felt he had to rigidly stick to what he told investigators.

A legal expert raised questions about a revelation made by Onuma about meeting with prosecutors to prepare for his court testimony.

Defense lawyers asked about such meetings and Onuma said he met with prosecutors at a rate of once a week from October 2019, about a year before he began testifying in court.

While the novel coronavirus pandemic temporarily suspended those meetings, Onuma said the gatherings resumed from June and there were times when he met with prosecutors three times a week.

The Supreme Court allows such preparatory meetings to ensure that proper questioning can be made in court.

But Tomoyuki Mizuno, a former judge who now is a law professor at Hosei University in Tokyo, said over-coaching might lead to changing what the person providing testimony says in court.

“Because Onuma avoided charges through the plea bargaining, there will be a need to be more careful in judging the reliability of his testimony,” Mizuno said. “He should not act in a way that might raise doubts.”