Mitsubishi Motors Corp., raided three times by the transport ministry over its decades-long fuel economy scandal, could be searched again by the regulator as a planned rescue by Nissan Motor Co. falls behind schedule.

The ministry may raid Mitsubishi Motors' offices a fourth time if the evidence collected during its latest inspection isn't enough to fully understand the scope of the automaker's misdeeds, said Yuki Ebihara, an official in the regulator's recall division. Another search also may be warranted if the ministry's findings point to bigger problems, he said.

"You can't deny the company has a culture that's prone to malpractice," Ebihara said in a phone interview. "Compared with other makers, we have to give them a closer look." Yuki Murata, an MMC spokesman, said the company regrets that its scandal has led to distrust and will cooperate with the ministry's investigation.