Italian police have arrested five people from Algeria, Tunisia and Libya on murder and human trafficking charges. They were among the survivors of the shipwreck off the Libyan coast that left more than 200 people missing at sea.

The men, who arrived in Palermo aboard the Irish Niamh rescue boat along with 362 migrants, are accused of causing the deaths of hundreds of people by trapping them within the hold of the boat after it started taking on water.

The fishing boat sent a distress call about 15 nautical miles north of Libya and capsized on 5 August when the Niamh got closer to the area, as migrants on the overcrowded vessel rushed to one side. Those who were on top of the vessel jumped into the water and were rescued, while the migrants who were travelling in the boat's hull were trapped inside.

Several survivors told investigators that sub-Saharan Africans were travelling in the boat's belly as they paid half of the price for crossing the Mediterranean from Libya to Sicily. The perilous Mediterranean crossing would cost migrants between $1,200 to $1,800. However, after three hours the boat ran into difficulty and water started flooding through the hull.

"On order of the smugglers, the migrants tried desperately to throw the water out," says a statement from Italian police. "Failing to do so, they attempted to escape to save themselves but instead they were hit by the traffickers with sticks and knives and forced back into the hull. The traffickers sealed the hatch with the weight of the remaining migrants," investigators said.

When the Irish rescue boat arrived, those who were stuck inside could not get out. It is believed that at least 200 people were travelling within the boat's hull. The five alleged traffickers - Rouibah Ali and Busadia Imad from Algeria, Mujassabi Suud and Assnusi Abdullah from Libya, and Esshaush Shauki from Tunisia - are all between 24- and 21-years-old.

They are accused of murdering at least 26 people - including 3 children - whose bodies were recovered by the rescue boats. Over 200 people are missing at sea and bodies have not been recovered.

Italian police also recorded several witnesses who reported horrific details of mistreatment. "Those who did not obey to orders were branded with knives in the head, especially the Africans. The Arabs, instead, were beaten with bells. The married men beaten with kicks and punches," the statement said.