Investigators have not yet ordered an expert vehicle examination of the pile-up on the Trakia motorway near Yambol, but they have already questioned 55 witnesses and people involved. Yambol regional prosecutor Doychin Doychev told Bulgarian National Radio (BNR) that it is too early for the examination.

The crash happened on Tuesday, 10 November. In thick fog near the Zimnitsa junction, more than 80 vehicles collided. Eleven people died. The National Investigation Service is leading the inquiry.

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"More than 50 witnesses have been questioned, but we expect to question about 100," Doychev said. Questioning continues. Yesterday, investigators from the service visited all hospitals to check on the condition of the injured and find out which of them can already give statements.

Investigators have filmed the whole crash site and carried out six inspections, some of them with a drone. They have seized 20 cars as evidence and will examine them again.

Prosecutors have asked the Road Infrastructure Agency for the documents on when this section of road was put into use and on its repairs. They have also asked for recordings from the toll cameras, which have yet to be reviewed.

Doychev said the recordings will be analysed together with the other data. They should show what the weather, visibility and traffic were like just before and after the crash, and which cars drove through the section.

The prosecutor said the experts need all the information to work out the cause of the crash. "To order the vehicle examination, we must collect as many witness statements as possible, as well as other evidence to give the experts," he said.