Prosecutors have opened a culpable homicide case over the death of Fiorentina captain Davide Astori.
The 31-year-old Italy defender was found dead in his hotel room in Udine on Sunday, hours before his team were due to face Udinese in a Serie A fixture.
A post mortem will be performed on Tuesday with Astori's funeral being held at the Basilica of Santa Croce in Florence on Thursday morning, Fiorentina announced in a statement.
Initial reports suggested Astori's death may have been the result of a cardiac arrest.
The chief prosecutor in Udine, Antonio De Nicolo, said today that a culpable homicide case would be opened, but that it was a formality at this stage and that "no one has a responsibility for anything".
He added in quotes published by Italian news agency ANSA: "An inquiry has been opened for culpable homicide against persons unknown.
"It is a duty to ascertain if the death of Astori came about through tragic fatality or if someone could have foreseen something.
"At this moment no one has responsibility for anything which would seem to us to amount to something.
"It permits us to individualise responsibility if there is any."
ANSA reported that investigators believed Astori had died of natural causes.
They said it was likely to have been a sudden death, and that he had exchanged a WhatsApp message with team-mate Marco Sportiello, whom he had played a PlayStation game with, at around 11.30pm on Saturday evening.
Investigators told ANSA that his hotel room was in order, and that he was found in bed under the blankets.
Fiorentina announced on Sunday morning that Astori had died following a "sudden illness".
All of Sunday's seven Serie A games were postponed as a result and tributes from across the footballing world poured in for the player, who won 14 caps for Italy.
Former clubs Roma, Cagliari and AC Milan - with whom Astori started his career but did not play a competitive match - were among those to offer their condolences, along with the likes of Real Madrid, Manchester City and Paris St Germain.
Chelsea coach Antonio Conte, who selected Astori during his reign as Italy coach from 2014 to 2016, told Sky Sports ahead of Sunday's Premier League match with Manchester City: "This is a tragedy and it really hurts me.
"It's very difficult at this moment to find the right words for the family.
"I had him with the national team. He was a great player but especially a fantastic guy. I stay close to his wife, parents and daughter. He was only 31 and it's very difficult to explain this situation."
UEFA announced today that there would a minute's silence in memory of Astori ahead of all of this week's Champions League and Europa League matches.