Early reports suggest that what caused Miley Cyrus tour bus to crash was likely that the driver suffered a cardiac arrest, but the report has not yet been confirmed by police.

Cyrus was not on board the bus, but the driver, 53 year-old William G. Douglas of Austin, Texas, was killed. Nine more people were on board but left with minor injuries.

The bus ran off the side of the road and flipped over last night in Virginia.

Some early reports based on 911 calls, suggest that the driver suffered an injury before the bus crashed, blogging site TMZ reported Friday.

Click here to listen to the 911 calls.