The transport ministry inspected 34 Bigmotor dealerships on Friday as part of an investigation into suspected automobile insurance fraud by the major used car dealer, amid a fresh allegation that the firm may have used herbicides on roadside trees so they would wither and increase the visibility of cars on display.

The surprise inspection, which covered dealerships in 24 prefectures, came after the ministry interviewed Bigmotor executives including newly appointed President Shinji Izumi on Wednesday. Based on the interviews, the ministry judged it needed to gather more information to determine whether the firm violated the road transportation vehicle law.

Bigmotor confirmed the inspection on Friday morning and said it will “fully cooperate” with the ministry.