(Bloomberg) — Carlos Ghosn was indicted on new charges of misdirecting company money for his personal use, the most serious allegations yet against the former chairman of Nissan Motor Co.

The new, third round of charges will keep Ghosn detained for longer as Japanese prosecutors pursue their case against the former global auto executive. Ghosn briefly won his freedom on bail in March, but was arrested and jailed again on new allegations of sending million of dollars from Nissan to accounts he controlled.

Another lengthy stay in prison, with limited access to his lawyers, could make it harder for Ghosn to prepare for a trial that may start later this year or next year. The executive, widely credited with saving Nissan from failure and bringing it together with Renault SA and Mitsubishi Motors Corp., was first arrested in November, sending shockwaves across Japan, France and the global auto industry.

Ghosn has denied the charges against him, blaming them on a “a very dirty game” by Nissan executives who were determined to oust him from the alliance. Ghosn has vigorously denied other accusations of transferring personal trading losses to Nissan and under-reporting his income.

Earlier on Monday, Nissan filed a criminal complaint against Ghosn for his actions. The Yokohama-based automaker sent a statement to prosecutors saying that it determined that payments made by Nissan to an overseas vehicle sales company via a subsidiary “were in fact directed by Ghosn for his personal enrichment and were not necessary from a business standpoint,” Nissan said in a statement.

“Nissan is requesting appropriately strict penalties,” the automaker said in the statement. “Nissan takes this unfortunate situation very seriously and again expresses sincere regret for any concern caused to our valued stakeholders.”

When he was first jailed, Ghosn lost 15 pounds (7 kilograms) and underwent hours of questioning daily. Two of Ghosn’s daughters told the New York Times in December that his cell wasn’t heated, that he had asked repeatedly for blankets and that he had been denied pen and paper. Another extended stay could refocus international attention on the workings of Japan’s criminal justice system.

Nissan, which swiftly removed Ghosn as chairman days after his first arrest, is seeking to turn over a tumultuous chapter in its ties with Renault. The sudden detention of the former global auto titan threatened to derail their partnership, the world’s biggest auto alliance.

Since then the three partners set up a new governance structure, led by Renault Chairman Jean-Dominique Senard, designed for smoother and more equitable decision-making.