An investigation dubbed Mare Aperto ('Open Sea') by the police of the province of Caltanissetta on Italy's island of Sicily has led to arrest warrants for 18 people allegedly involved in a migrant smuggling ring.

Eleven Tunisians and seven Italians stand accused "of participation in a criminal association for the aggravated aiding and abetting of clandestine [transnational] immigration," according to the local prosecutor's office.

The charges against the suspects were considered aggravated in part because they put the lives of migrants at serious risk and allegedly subjected them to inhumane and degrading treatment, police said in a statement about the operation released on Thursday (November 17).

Police said that they were able to arrest 12 suspects; but they were reportedly unable to track down six of the alleged ring members, likely because they are abroad, and are still searching for them.

Prosecutors had ordered investigative custody for 12 of the suspects and house arrest for six, according to police.

Migrants allegedly paid up to €5,000 per person

Police said that they believe that the alleged smuggling ring used "small boats, equipped with powerful outboard engines, operated by expert smugglers ... between the Tunisian cities of Al Haouaria, Dar Allouche and Korba and the [Italian] provinces of Caltanissetta, Trapani and Agrigento." This meant that the boats could reach Italy from Tunisia in less than four hours.

The smugglers transported between ten and 30 people per time, who paid between €3,000 and €5,000 in Tunisia prior to the departure, according to investigators -- meaning that the alleged gang made between €30,000 and €70,000 in revenue per trip.

The money collected in Tunisia was reportedly sent to Italy through international agencies specialised in money transfer services, and later deposited onto debit cards used by the supporters of the organization.

Smuggling boat found adrift triggered investigation in 2020

The investigation was kicked off by the discovery of a boat adrift off Sicily, according to the police's statement.

On July 26, 2020, one of the boat's used by the suspects reportedly had an engine failure during the trip from Tunisia to Italy, leaving the boat drifting in the "open sea" -- the reason behind the name given to the operation by the police. The boat was then found off the coast of Mazara del Vallo, according to police. (The police did not release information about what happened to the migrants on board the boat.)

Suspects operated in Italy and Tunisia

Investigators believe that the organization was led by a Tunisian man and woman who had already been placed under house arrest for similar crimes prior to the recent arrests, as well as an Italian, who managed the operations from the Sicilian town of Niscemi.

Four people are suspected of smuggling the migrants from Tunisia to Italy -- three Tunisian nationals and one Italian. Two Tunisians based in Scicli, (another Sicilian town in the south of the island), are suspected of managing the finances of the organization. Five Italians are suspected of handling logistical aspects of the operation in Italy (such as housing for migrants or transferring smugglers from bus stations to operating bases). And four Tunisians allegedly connected the organization to clients in Tunisia, which reportedly included collecting the money from migrants.