Ms Englaro opposed being kept alive artificially, her father said
The father of a woman who was at the centre of a right to die battle which split Italy is under investigation for murder, prosecutors have said.
Eluana Englaro died on 9 February after doctors removed her feeding tubes. She had been in a coma since 1992.
A court had ruled her treatment could be stopped in accordance with what her father said were her wishes.
Charges will not necessarily arise from the investigation, which was triggered by pro-life groups.
Eluana's father, Beppino Englaro, 67, is one of 14 people named in the inquiry by prosecutors in north-eastern Italy's Udine region.
The others include her Eluana's anaesthetist and other members of her medical team.
The investigation was brought about by a suit launched by a pro-life group calling itself the Truth and Life Committee.
Prosecutors must act on such suits even if there is no evidence of wrongdoing, lawyers say.
In an interview with the BBC, Mr Englaro said he had been informed that he had been placed under investigation, but did not know much more about the allegations.
"I have always acted within the law, so from this point of view I feel completely fine," he said.
He said that he and Eluana's medical team had "dealt with this difficult issue in the light of day and in the right way".
"It was a unique case, so we were all very cautious," he added.
"I realised from the beginning that people struggled to understand the meaning of freedom. Eluana is a symbol of this freedom."
Eluana, 38, had been in a coma for 17 years, following a car accident in 1992.
Beppino Englaro is one of 14 people named by prosecutors in the inquiry
In a landmark ruling, a court said last year that it was satisfied her condition was irreversible and that she had clearly expressed her wish not to be kept alive artificially.
She died of a heart attack, just a few days after her feeding was stopped. A preliminary autopsy showed no signs of foul play. Results of a toxicology report will be released on 1 April, Ansa news agency said.
The case has deeply divided opinion in strongly-Catholic Italy.
The court ruling was opposed by the government and the Vatican, which said it amounted to euthanasia.
Shortly before she died, the senate rushed to discuss emergency legislation that would have banned the removal of feeding tubes.
Politicians have said they will work to clarify Italy's right-to-die laws.
Euthanasia is illegal but patients have the right to refuse care.