De Villota, 33, lost her right eye and fractured her skull in a horrific accident at a straight-line test at Duxford airfield in England in July 2012. She recovered from life-threatening injuries but no longer competed.
"We are assuming it was a natural death, but we cannot confirm anything," the police spokeswoman said, adding that forensic scientists and police from the homicide unit were to examine the scene.
De Villota was appointed test driver for Anglo-Russian Formula One team Marussia last year, before her crash. However she never took part in a general test with other drivers.
Only a handful of women have driven Formula One cars in the last decade and none has come near to racing one in competition.
Image: Maria de Villota
Photograph: Mark Thompson/Getty Images
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