German car manufacturers Audi have confirmed Michele Alboreto's fatal crash was caused by a ruptured tyre.

The 44-year-old Italian died when his Audi R8 lifted into the air and flipped over on a high-speed straight section of the Eurospeedway circuit at Lausitz near Dresden last Wednesday.

Chief Cottbus prosecutor Petra Hertwig, who is heading the investigation into the cause of the crash, admitted on Sunday the rear tyre was damaged - but revealed they were still looking into other possibilities.

But Audi experts, along with German technical inspection group Dekra, who were called in by the Cottbus prosecutors to help find out the cause of the crash, agreed the ruptured tyre was the reason for the crash.

"Our investigation so far has determined that a sharp object penetrated the left rear tyre, leading to a gradual loss of pressure," said a statement from Audi, quoting an expert from Dekra.

The former Ferrari driver was travelling at 185 mph testing the Audi for this summer's 24-hour race at Le Mans.

Audi will go ahead with plans to race at Le Mans now that it has been confirmed the accident was not caused by a technical problem.