The National Investigation Service has taken over the probe into the pile-ups on the Trakia motorway that killed 11 people and injured dozens. Investigators and forensic officers worked at the scene until late at night, and a second inspection is expected there today.
More than 80 vehicles crashed in thick fog on Tuesday near the Zimnitsa interchange, close to Yambol. The same day, the Vazrazhdane party called for personal responsibility for any failings, if any are found. The crash is among the worst on Bulgaria's roads.
Earlier on this story: Vazrazhdane calls for personal responsibility for the crashes on «Trakia» near Yambol
Early findings point to thick fog and sharply reduced visibility as possible factors. It is not yet clear whether the weather was the only cause.
Investigators want to know in what order the collisions happened, how fast the cars were going, whether drivers kept a safe distance and whether they had time to react. A vehicle technical expert report will show how the crashes happened.
Police are still questioning witnesses, and investigators will go through all available video footage.
Dozens of tow trucks and car transporters are clearing the road. They started work after 6.30pm the previous evening.
Police and firefighters will hold a joint briefing later this morning.