Five migrants have been arrested in Italy on the suspicion that they stabbed a number of people to death and threw their bodies overboard in last Sunday’s migrant tragedy. Three others were charged with human trafficking.

At least 29 people died on the boat’s lower deck, apparently from drowning, but reports in the international press suggest that other migrants were killed and their bodies were thrown overboard during the voyage.

Survivors of the latest migrant tragedy told investigators that a fight broke out as persons who were riding in the hold, suffocating from heat and a lack of oxygen, tried to climb on the upper deck. It is understood that the latch to the lower deck was forced shut and a ladder was removed. Conditions soon became unbearable with the intense heat emitted by the engine and the lack of oxygen and those below forced the door open and tried to climb onto the upper deck.

According to the testimonies of a number of eye witneses, the five men – two Moroccans, a Saudi Arabian, a Syrian and a Palestinian – launched into a stabbing and punching frenzy to try and stop those below from climbing up to the main deck. They then threw the  bodies of their victims overboard and warned the other migrants not to react or face the same end.

In the meantime, autopsies on the 29 bodies that were brought to Malta on Sunday have established the cause of death to be drowning, according to reportds. All 29 were riding in the lower deck. Eerlier reports had suggested that the migrants suffered carbon monoxide poisoning. The boat was towed to Malta by an AFM patrol boat.

In all 561 migrants were rescued and taken to Sicily on Sunday.