TOKYO — Carlos Ghosn, the former head of Nissan Motor, slammed the company’s management on Tuesday, arguing that the same executives he says engineered his downfall from the top of a vast auto empire are running the Japanese automaker into the ground.

In a video statement played at a hastily assembled news conference, Mr. Ghosn, who currently sits in a Tokyo jail, reiterated that he was innocent of charges of financial impropriety brought against him by Japanese prosecutors. The accusations, he said, are part of a plot carried out by Nissan executives who were afraid he was planning to turn the company into a subsidiary of its alliance partner Renault.

But then he shifted gears. The real victim of the intrigue, he said, is not Carlos Ghosn but Nissan. He said the accusations against him stemmed from a plot by Nissan executives trying to draw attention away from years of bad results at the company.

[Behind the scenes, Nissan seethed with internal tensions and worries about being absorbed by Renault.]