In one aspect of their internal probe, company investigators are looking into decisions made in the United States by Jose Munoz who led Nissan's North American operations from 2014 to 2018, the people said. Munoz was recently placed on a leave of absence due to the probe, they added.
Nissan said this month that Munoz, its chief performance officer and widely seen within the industry as close to Ghosn, was on leave "to allow him to assist the company by concentrating on special tasks arising from recent events."
Munoz is not cooperating with investigators, two of the people with knowledge of the probe said, both describing his actions as "stonewalling".
One of the sources described Munoz, who currently heads Nissan's China operations, as a "person of interest" in the probe, adding that it was not clear whether he would be accused of any wrongdoing.
Munoz, 53, did not reply to Reuters requests for comment. The people with knowledge of the probe spoke to Reuters on condition of anonymity due to the sensitivity of the matter. A lawyer for Ghosn, Motonari Otsuru, said in an emailed comment: "I am unaware of this."
Some of the questions put to Munoz relate to dealer franchise rights, one of the sources said. Other questions relate to contracts with parts suppliers and service providers that Munoz approved when he was at the helm of Nissan's U.S. operations, another source said.
The sources said the findings made as part of the probe into Ghosn's affairs in the U.S. market are being shared with prosecutors. Tokyo prosecutors declined to comment.
Nissan has said its internal investigation had uncovered "substantial and convincing evidence of misconduct" by Ghosn and that its scope is expanding.
Ghosn, once the most celebrated executives in the auto industry and the anchor of Nissan's alliance with France's Renault SA, has been charged with under-reporting his income. On Friday, he was also charged with aggravated breach of trust, accused of shifting personal investment losses worth 1.85 billion yen ($17 million) to Nissan.
In his first public appearance since his Nov. 19 arrest, Ghosn declared his innocence in court on Tuesday, saying he had never received compensation that was not disclosed and that Nissan had not suffered any losses due to a temporary transfer of a personal foreign exchange contract.
The transfer had been a temporary measure to prevent him from having to resign and use his retirement funds as collateral, Ghosn said.
Sources familiar with the matter have also said Nissan investigators are examining other dealer franchise decisions in several countries where Ghosn played a part in the decision-making to see if there had been any misconduct.
In particular, the automaker's investigators are looking into Ghosn's role in what Nissan insiders have described to Reuters as a surprise decision in 2008 to pick a company called Hover Automotive India Pvt Ltd (HAI) as Nissan's partner for marketing, sales, after-sales service and dealer development in India.
A different firm, TVS, had been lined up for the role after much research by Nissan management in India when Ghosn personally intervened at the last minute to push for HAI, four Nissan insiders said. They add that in 2012, HAI became the Nissan's exclusive national sales firm in India, despite being relatively inexperienced in distributing vehicles to dealers.
Reuters was unable to find a representative for HAI, which according to India's Registrar of Companies was dissolved as of Sept. 11, 2018. TVS did not respond to a request for comment.
The probe is also looking at what appear to be outsized payments for Ghosn's bodyguard services in Brazil, one of the sources said.
Ghosn's lawyer Otsuru did not respond to requests for comment on the expansion of Nissan's probe into dealings in India and Brazil. A U.S. representative for Ghosn declined to comment.
One source also said Nissan is conducting audits of some distribution partners in the Middle East, including Saudi Arabia's Al-Dahana which owns half of a joint venture called Nissan Gulf with the other half held by a wholly owned unit of Nissan Motor.
Al-Dahana, a marketing and dealer development firm, is majority owned by Khaled Al-Juffali, vice chairman of one of Saudi Arabia's largest conglomerates. Reuters has reported that Al-Juffali is the person prosecutors believe arranged a letter of credit for Ghosn over his foreign exchange contract after which a company that Al-Juffali owned received four payments totaling $14.7 million.
Both Ghosn and the Khaled Juffali Company have asserted that the payments were for legitimate business purposes. Asked about the audit, a representative for the Khaled Juffali Company said the firm stood by its previous statement.
Another Nissan executive, Arun Bajaj, senior vice president for human resources and who heads talent development for Nissan's alliance with Renault and Mitsubishi Motors Corp, has also been put on a leave of absence "to assist the company by concentrating on special tasks arising from recent events."
Bajaj is being questioned and is cooperating with both Nissan's internal investigators as well as prosecutors, the sources said, adding that they expect him to return to work soon. It was not immediately clear what the questions were about. Bajaj did not respond to a Reuters request for comment.
Ghosn is unlikely to be granted bail and is expected to remain in detention throughout his trial as is often the case under Japan's criminal system, Otsuru told reporters this week. Ghosn's trial may not begin for another six months, he added.
Reporting by Norihiko Shirouzu; Additional reporting by Tim Kelly, Kiyoshi Takenaka, Mike Spector, Aditi Shah and Saeed Azhar.