Authorities have detained eight suspected smugglers over the deaths of 49 migrants trapped inside the hold of an overcrowded fishing vessel over the weekend, an Italian prosecutor said.

Michelangelo Patane, speaking in Catania, said a Moroccan was the captain of the ship while the other seven – four Libyans, two Moroccans and a Syrian minor – used violence to keep order.

Patane said the air below deck was not breathable because of the number of people and engine fumes, and that the smugglers hit those trying to get out with belts and kicked them in the head, “preventing them from having some chance of survival”.

Authorities said they had additionally identified 116 Moroccans among more than 360 passengers who will be expelled and returned to Morocco.