Formula One test driver Maria de Villota was found dead in her Seville hotel room on Friday due to injuries she sustained at a prior crash. She was 33 years old.

An autopsy reveals that the test driver died of natural causes, specifically, neurological injuries brought on by her 2012 crash, Daily Mail UK reports. Her sister, Isabel de Villota, confirmed the results of the autopsy. "Maria died in her sleep," she said in a statement.

De Villota was in Seville to speak at a conference organized by human values advocate, What Really Matters. She was scheduled to launch and promote her book "Life is a Gift" today in Madrid.   

"I hope that, without having to go through an accident like mine, you can feel the joy of being alive and enjoy life," she wrote in the introduction to her book.

De Villota suffered debilitating injuries that left her in a coma for months and resulted to the loss of her right eye following her near-fatal Duxford crash. De Villota was testing an MRO1 race car for the Marussia team at the Duxford airbase in Cambridgeshire, England last year when she lost control of the vehicle and hit a Marussia support truck, according to a video report shared by Speed Magazine TV on YouTube.  

De Villota was last scene publicly with her husband and personal trainer Rodrigo Garcia in Santander. Photos of the happily married couple, where they were captured jogging and walking their dog, can be seen on the Daily Mail Online website.

The Daily Mail also reports that Maria had sent Spain's Yong Sport Foundation director Alfonso Jimenez an email invite to her book launch at midnight. She died at 6:00 AM on Friday. 

De Villota will be buried in a private ceremony in Madrid, Isabel told the AFP.

De Villota was the first Spanish woman to join F1 after filling the ranks of the Marussia F1 Team last year as a test driver. Her father, Emilio de Villota was also an F1 driver. News of her death left the motorsports world, where she was greatly admired and hailed as a pioneer, grieving and in shock.