"When a boat approached us, we thought we were being rescued -- instead, as soon as it got closer, we saw it was a Tunisian fishing vessel. Fearing a repeat of what had occurred a few days before, when others were robbed of their engine, we decided not to talk to the fishermen, but the six crew members told us we had to give them our engine," said one of the migrants aboard the 49-person migrant boat, which set off from Sfax in Tunisia.

The boat was allegedly robbed on August 12 by fishermen-turned-pirates. The six crew members have been arrested and face charges between 10 and 20 years if convicted.

Six Tunisians in Agrigento prison

Agrigento's flying squad, finance police and port authority officials questioned witnesses.

The arrest of the six Tunisian nationals -- carried out at the request of Agrigento chief prosecutor Salvatore Vella -- was confirmed by preliminary investigations judge Stefano Zammuto, who ruled in favor of pre-trial detention for all six suspects on piracy charges.

"Our skipper tried to leave but did not succeed, also due to the rough sea that made any maneuver difficult. Fearing for our safety, we accepted to tie our boat with a rope to the Tunisian fishing vessel," the migrant said.

Once the two boats were side by side, a fisherman leaned over and stole the boat's engine, the migrant continued.

"Everything happened despite our protests: we understood that we were in danger without an engine," they said. "The Tunisian fishermen told us they wouldn't leave us at the mercy of the waves and would wait for rescuers."

Although the fishing vessel towed the boat for a short while, crew members aboard eventually dropped the rope and sailed away, the witness said.

'We were desperate'

The witness told investigator that the Tunisian fishermen came back around two hours after leaving the migrant boat behind.

"Many of us were crying because we were scared. They started throwing bread to us, probably to calm us down. They tried to reassure us and they said that, if we gave them our money, they would wait for help to arrive. Since we didn't have any other hope, we gave in and handed over a total of 150 Tunisian dinars, which we put inside a hat and threw it on the fishing vessel," the migrant said.

After getting the money, the Tunisian crew members "continued to tow us for about an hour, until, in the distance, we saw an Italian rescue vessel approach us.

At that moment, the fishing boat turned around and left quickly."