A two-truck accident on Indiana’s Interstate 70 left one driver dead. Police still are trying to figure out what caused the August 17 accident.

According to witnesses and officials, both semi trucks were moving through a construction area on Wednesday. Traffic was reportedly coming to a stop, with the lead Volvo semi slowing down accordingly. At that time, the truck behind the Volvo crashed into the lead truck, crushing into the towed box trailer on the first vehicle, apparently at some speed.

Emergency crews arrived quickly on scene and attempted to free the driver of the second truck. However, tragedy struck within a few moments as the cab abruptly caught fire. The fire spread so quickly and became so intense that the rescue crews were forced to retreat before they could get the driver out of the vehicle. Firefighters had to spend two full hours constantly fighting the inferno to bring it under control, and the driver of the second rig was ultimately pronounced dead at the scene.

The deceased driver was not identified, pending notification of his family or next of kin, apart from police confirming he was from Ohio and driving for the Tennessee-based company Averitt Express Inc. The driver of the Volvo semi was one Kundan S. Randwaha, a 57-year-old native of Ontario, Canada. Randwaha was surprisingly not injured in the collision or the subsequent fireball.

As said above, police are still unsure what caused the accident. The damage to the second vehicle was extensive, and it may be some time before they can figure out if it was driver error or some manner of mechanical failure that kept the unidentified driver from stopping in time. There is also no word yet on why the cab suddenly combusted following the accident, though a fuel leak is suspected.