Police searched the offices of a bus operator on Tuesday, a day after a fatal crash on an expressway in Nagoya city, central Japan.

Aoi Kotsu in Komaki city, north of Nagoya, was the operator of the bus. The bus overturned and caught fire on Monday morning. It was heading for Nagoya Airport from the city center. Two people on the bus died. Six passengers and the driver of a vehicle that collided with the bus were injured.

Police searched the bus operator's offices including its headquarters on suspicion of negligent driving resulting in death and injury.

They are expected to confiscate materials in order to examine the driver's work conditions and the firm's safety management.

Sources say the bus hit a divider while traveling in the lane that led to the expressway exit. They say there were no brake marks at the scene. Police plan to look into how the driver steered the bus just before the crash and his condition at that time.