The cause of de Villota's death was not immediately apparent, though police said they found no signs of violence, The Guardian newspaper reported.
"We are assuming it was a natural death, but we cannot confirm anything," a police spokeswoman said, adding that forensic scientists and homicide detectives were investigating the scene.
De Villota underwent major surgery to rebuild her face and skull in November after she crashed a Team Marussia car in July at the Duxford, England, test track. It was her first drive after beginning work for the team.
The driver's family released a statement Friday about her death.
"Dear friends: Maria is gone. She had to go to heaven with all of the angels. Give thanks to God for the year and a half we had left together. Signed, the Villota family," the statement read.
De Villota was expected to launch an autobiographical book about her accident, "Life is a Gift," on Monday, La Vanguardia.com reported.