Prosecutors in Sicily detained 10 people on suspicion of smuggling and murder for allegedly cramming dozens of migrants into the airless hold of a boat where 52 bodies were found.
The Swedish ship Poseidon rescued 439 survivors of the boat on Wednesday but found 52 bodies after looking into the hold.
Rescuers had to smash the deck to reach the corpses.
Carmine Mosca, head of the Palermo police squad, said survivors who came ashore on Thursday told authorities how the smugglers would beat the migrants back with knives if they tried to come out of the hold for air.
“When theses migrants tried to relay their need for air and water, they were mishandled, injured, knifed in a truly fierce way,” Mr Mosca said.
Palermo prosecutor Maurizio Scalia said the detained crew included seven Moroccans, two Syrians and a Libyan who was the “violent” enforcer of order on the ship.
The migrants hailed mostly from sub-Saharan Africa but also Pakistan and Bangladesh.
Officials believe the cause of death was likely to have been asphyxiation.
Mr Scalia said the hold of the 20-metre boat contained about 60 people and was only about a metre high, with two small windows and the boat’s engine.
Murder charges
Mr Scalia said murder charges, rather than manslaughter, were warranted since the smugglers “eventually accepted the risk that these people, in these conditions, could die”.
In previous crossings, the smugglers would charge an extra €4,000 apiece for places above deck and an additional fee if they wanted life jackets.
However, that distinction was not used in this operation, Mr Mosca said.
The crew leader simply directed the migrants above or below deck as they boarded, regardless of what they had paid, he added.
PA