An Italian prosecutor has revealed that five people have been arrested on suspicion of murder after more than a dozen illegal immigrants were thrown from a boat in a 'voodoo ritual to calm stormy seas.

Survivors spoke of how the Nigerian captain picked people as human 'sacrifices' after the engine failed on the crammed ship carrying 400 people. The victims were allegedly picked on ethnic origin or nationality. Witnesses described women on board performing a macabre 'magic dance' before the victims were flung overboard to 'calm the seas and placate the devil'.

The ship was sailing from Libya to the Italian island of Lampedusa. It was eventually escorted into harbour by coastguards after it sent a mayday signal.  25 people who had suffocated due to the poisonous fumes from the engine and the cramped squalid conditions on board were found dead in a hold when the ship reached port. Dozens of others were rushed to hospital suffering from dehydration and exhaustion.

As part of the investigation police interviewed survivors found on the boat and taken to accommodation centres across southern Italy.