As the investigation into the sinking of the superyacht off the coast of Sicily broadens, Italian prosecutors are now scrutinizing the actions of two other crew members in addition to the captain of the vessel.

On Wednesday, prosecutors placed crew members Tim Parker Eaton and Matthew Griffiths under investigation, according to The New York Times . Eaton was in charge of the yachts engine room, while Griffiths was on lookout duty the night the yacht sank.

When someone is placed under investigation in Italy, there is no guarantee that charges will follow.

The Bayesian, a 184-foot British-flagged yacht deemed unsinkable by its ship maker Perini Navi, went down in a storm off the coast of Sicily on Aug. 19, killing one crew member and six passengers, including British tech magnate Mike Lynch and his 18-year-old daughter, Hannah.

The yacht carried 22 people 10 crew members and 12 guests who were there celebrating Lynchs acquittal in June on all charges in a fraud case that followed the sale of his company Autonomy to Hewlett-Packard for $11 billion in 2011.

Fifteen of the 22 people aboard survived by escaping on a lifeboat and were rescued by the sailboat Sir Robert Baden Powell. It remains unclear how the Bayesian sank, especially as the nearby Baden Powell remained largely unscathed despite the storm.

According to The Associated Press , Giovanni Costantino, head of the Italian Sea Group, which owns Perini Navi, said the yachts sinking was likely caused by human error.

The ship sank because it took on water. From where, the investigators will say, he told Italian state media, per the AP.

Captain James Cutfield is facing a manslaughter inquiry to determine whether his actions caused the shipwreck, Cutfields lawyer Giovanni Rizzuti told the Times on Tuesday. Prosecutors interviewed Cutfield this week, but he exercised his right to remain silent and is very distressed, according to Rizzuti.

This week, nine of the 10 crew members, including those under investigation, left Sicily, sources told the Times. In Italy, people under investigation are not prohibited from leaving the country.