Argentine prosecutors were on Friday investigating the circumstances surrounding the death of Diego Maradona to ascertain whether it could have involved medical negligence, judicial sources said.

“There are already irregularities,” a close family member said.

Maradona’s lawyer, Matias Morla, had earlier called for an investigation into claims that ambulances took more than half an hour to reach the football star’s house in response to an emergency call on the day of his death.

A preliminary autopsy report established that Maradona died in his sleep at noon on Wednesday of “acute lung edema and chronic heart failure.”

The prosecutor’s office in Buenos Aires has opened a file entitled “Maradona, Diego. Determination of the cause of death.”

“The case was initiated because he is a person who died at home and no one signed his death certificate. It does not mean there are suspicions or irregularities,” a judicial source said, requesting to remain anonymous.

The 60-year-old Argentine football legend was receiving round-the-clock medical care at a house in a gated community in Tigre, north of Buenos Aires, where he was recuperating from surgery to remove a clot on his brain in early November.

“You have to see if they did what they were supposed to do or if they relaxed,” the family member told AFP.

 “The nurse made a statement when the prosecutor appeared on the day of Diego’s death, then expanded her statement and finally went on television to say that what she said was forced on her, so there is some contradiction in her statement,” the close relative said.

The prosecutor’s office is awaiting the results of toxicological tests on Maradona’s body.

The three prosecutors working on the case have requested the star’s medical records, as well as recordings from neighborhood security cameras.

Another nurse caring for Maradona was likely the last person to see the star alive, at dawn on Wednesday, prosecutors said in a statement on Friday.