TERMINI IMERSE, Italy — Prosecutors said there “could be a question of manslaughter” as they opened an investigation into the deaths of seven people after a superyacht sank while anchored off the Sicilian coast Monday.

Speaking at a press conference, prosecutor Ambrogio Cartosio said the investigation is not currently directed at any individuals, and is looking into “the crime of culpable shipwreck and multiple manslaughter.”

“But we are only at an early stage,” Cartosio said. “Developments in the investigation could be of any kind, and we are not ruling anything out.”

Twenty-two people were onboard the 184-foot Bayesian when a sudden and violent storm struck before dawn on Monday, Aug. 19. Divers embarked on a challenging rescue operation, recovering seven bodies from the wreckage. The vessel was anchored about a half-mile offshore when it sank, leaving divers to search its hull on the seabed 164 feet underwater.

There were 15 survivors, including all but one of the ship’s crew.

Cartosio said that the sinking could have been caused by “behaviors that were not in order.”

Taking questions from reporters, prosecutors asked about the crew’s responsibilities said they were “concentrating on this particular aspect,” adding they wanted to “discover how much they knew and to what extent all the people were warned.”

They said that the passengers who died were probably asleep, and that this is the reason they failed to escape.

Prosecutors also confirmed that the captain of the Bayesian will undergo more questioning. New Zealander James Cutfield has already been questioned for more than two hours, and prosecutors said he had been “extremely cooperative.”

The prosecutor said that there was no legal obligation for the captain, crew and passengers to remain in Italy, but expected them to “cooperate fully” in the investigation.

Bad weather was forecast ahead of the sinking, and questions about the weather were also raised by journalists.

“Apart from extreme events which are being verified by the prosecutor, there was a great deal of visibility,” an official said according to a translation by Sky News, NBC’s partner network in the U.K.

Based on forecasts from midnight to 4 a.m. on the Monday that the ship sank, he added that “there wasn’t anything to suggest there could be an extreme situation arising.”

The accounts of survivors that have emerged through the Italian medics who treated them have suggested the sinking took place in mere minutes and came as a shock.

Prosecutor Raffaele Cammarano added that “The investigation, which will be based on the recovery and then on the analysis of the wreck, will allow us to obtain answers to questions that remain unknown.”

The body of British tech magnate Mike Lynch — regularly described in U.K. media as “Britain’s Bill Gates” — was among those recovered from the wreck. His 18-year-old daughter, Hannah, was the last to be found after the five-day rescue operation.

The others casualties were Lynch’s associates and their partners, including one of the lawyers who had successfully defended him in a blockbuster U.S. fraud trial earlier this summer: Jonathan Bloomer, chairman of Morgan Stanley International and the British insurance firm Hiscox, and his wife, Judy; and a well-known New York City defense attorney, Christopher Morvillo, and his wife, Neda.

The body of Recaldo Thomas, a Canadian Antiguan national who was the ship’s cook, was recovered shortly after the accident.

Prosecutors said that autopsies had not yet been done.