PARIS - A Renault SA security agent under investigation for his role in an industrial-espionage case has money in a Swiss bank account, but he put it there to pay a company informant, not for his personal use, his lawyer said Wednesday.

Dominique Gevrey has been held in detention since the weekend, as prosecutors try to unravel the circumstances that led the French auto maker to dismiss three senior managers in January. Renault, which had accused the trio of taking bribes in exchange for divulging strategic corporate information, admitted Monday that they had been falsely accused, and it apologized to them.

Attention has now turned to money Renault spent during an internal investigation last year that led to the three men's dismissal.

The Paris state prosecutor, Jean-Claude Marin, said Monday that Renault had paid out €300,000 ($419,800) to cover the cost of the probe, and had an additional €400,000 in bills waiting to be paid. Mr. Marin said the evidence pointed to Renault having been the victim of an organized attempt to defraud it.

On Wednesday, Mr. Gevrey's lawyer, Jean-Paul Baduel, said that Mr. Gevrey had put money from Renault in a Swiss bank, where it was set aside to pay an informant on the company's behalf.

"There is money in a Swiss bank account," he told The Wall Street Journal. "Because the spy wants to be paid."

He said Mr. Gevrey was innocent and had told prosecutors about his bank account voluntarily. "Everybody is thinking it's a fraud," he said. "But the problem is, there is a lack of evidence."

Renault has faced criticism over its handling of the case, in particular from the French government, which owns 15 percent of the company. On Wednesday, Industry Minister Éric Besson called for an audit of Renault's governance practices.

Chief Operating Officer Patrick Pélata offered his resignation Monday, but Chief Executive Carlos Ghosn declined to accept it. Instead, Mr. Ghosn apologized to the three managers on national television, and said that he, Mr. Pélata and other senior managers would forfeit their 2010 bonuses and some stock options.

Analysts say the incident probably won't affect Renault's sales significantly, though it had tarnished the image of the company and Mr. Ghosn.