Nissan Motor Co.'s auditor questioned transactions by a subsidiary that may have a bearing on allegations of financial misconduct that led to the arrest of ousted chairman Carlos Ghosn.

The auditor expressed its concerns several times around 2013 about acquisitions of several luxury properties overseas that were offered for Ghosn's private use, and wanted to know precisely what the subsidiary was set up to do.

Nissan responded that everything was aboveboard with regard to the subsidiary, Zi-A Capital BV, based in Amsterdam, sources said Dec. 2.

The subsidiary's board members included former Nissan representative director Greg Kelly, 62. He and Ghosn, 64, were arrested Nov. 19 on suspicion of under-reporting Ghosn’s remuneration.

An executive of the secretary’s office of Nissan also served as a board member of the subsidiary and was involved in the creation of documents that stipulated the carmaker would defer a portion of Ghosn's annual remuneration until after his retirement.

Along with a Nissan corporate officer, the executive who had served Ghosn for many years reached a plea-bargaining deal with the Special Investigation Department of the Tokyo District Public Prosecutors Office.

Ghosn, who is alleged to have violated the Foreign Instruments and Exchange Law, is being held at the Tokyo Detention House.

Prosecutors suspect that a limited number of aides may have assisted Ghosn in his financial dealings, sources said.

The Amsterdam-based subsidiary was established in 2010 with about 6 billion yen ($53 million) in capital to make investments in venture businesses.

It purchased luxury properties in Rio de Janeiro and Beirut through a sub-subsidiary it set up in the British Virgin Islands, a tax haven.

The Brazilian-born Ghosn also has French and Lebanese nationality.

The costs to purchase and maintain the properties amounted to several billions of yen. The house in Beirut required extensive renovations under local regulations as it is located in a historic district.

The homes were offered to Ghosn and his family members for their private use.

According to the sources, the auditing company told the carmaker several times around 2013 that the subsidiary’s activities in investing in venture businesses were unclear.

The subsidiary was not subject to Nissan’s financial results on a consolidated basis, and for this reason was not covered by the audit.

Even so, the auditor noticed the problem while checking the flow of funds from and into Nissan.

However, company officials explained that the subsidiary was engaged in making sound investments and there was nothing to worry about.

The special investigation department now has a clearer idea of why the overseas properties were purchased.

Ghosn told investigators that the properties were necessary because he frequently traveled around the world on business, the sources said.

Kelly told investigators that Ghosn had planned to purchase the homes at appropriate market prices after his retirement.