The Spaniard, 33, died of a suspected heart attack, with early reports in her home country linking it to the trauma of a major accident she suffered in the UK last year.
The Health and Safety Executive said an investigation into the accident at Duxford airfield in Cambridgeshire was continuing and any post-mortem findings and other developments following her death would be considered.
De Villota, whose father Emilio made two starts for McLaren in the 1977 season, was found dead in her hotel room in Seville where she had been due to appear at a conference on Friday entitled “What Really Matters”. The conference was suspended according to reports in Spain.
Investigators said they had “not found any drugs or signs of violence” adding that “everything points to a death by natural causes”. A spokeswoman for Madrid police added: “We are assuming it was a natural death, but we cannot confirm anything.”