A Greek public prosecutor on Tuesday ordered the captain and second officer of the sunken ferry Express Samina to be jailed pending trial on charges of manslaughter, an investigating magistrate said.
The ferry hit a well-charted islet and sank last Tuesday, killing at least 79 people, just before reaching the Aegean island of Paros.
It was reported that prosecutor Dimitris Dadinopoulos also formally charged the two with exposing passengers to danger resulting in death, causing a shipwreck and a series of lesser charges in what was Greece deadliest sea tragedy in decades.
Captain Vassilis Yannakis has reportedly said he was unwell and taking a nap shortly before the crash. His number two, Tassos Psychoyios, reportedly told investigators he tried to steer the ship away from the rocks but that bad weather had prevented him.
They will be transferred to a prison on the island of Chios, where they can be held up to 18 months without trial, Karabassi said.
Two other seamen, the helmsman and a trainee captain, who were on the bridge at the time, are also being held and may also face manslaughter charges.