A police statement said that the suspects allegedly asked for €3-5,000 in cash per person and had considered throwing passengers overboard in the case of problems along the journey.
Police in Italy have arrested 12 people on Thursday over their alleged roles in a high-speed migrant-smuggling ring that operated between Tunisia and Sicily.
They also issued warrants for a further six individuals who are thought to be involved.
A police statement said that the suspects allegedly asked for €3-5,000 in cash per person, packed the boats with 10 to 30 passengers at a time, and themselves made €30-70,000 from each of the journeys.
Intercepts of phone conversations also revealed that the traffickers had considered dumping the migrants overboard if problems were to arise in the midst of the perilous journeys, police reported.
The investigation was launched in February 2019, after a Sicilian fisherman from the coastal town of Gaeta noticed a 10-metre glass fibre boat with two 200-horsepower motors.
Investigators found that the boat had been stolen 10 days before the incident in Catania, Sicily.
Arrest warrants were issued for 11 Tunisians and seven Italians, with the scheme's purported 'masterminds' being a Tunisian couple already imprisoned for human trafficking.
The warrants also targeted four other alleged speed-boat drivers, one Italian and three Tunisians, and four Tunisians who connected with the migrants in northern Africa.
Another of the suspects is a farm-owner with a private airfield, thought to have been the operation's base. The farmer was accused of offering employment documents to some of the Tunisian operatives to legitimise their presence in Italy.
Two Tunisians based in Sicily were accused of having managed the money, while five Italians are believed to have organised housing and travel arrangements. Profits were reinvested into the scheme, including the purchase of new boats, to increase earnings.
The suspects now face charges of illegally smuggling over five people across borders, with their alleged mistreatment of the migrants' lives and plans to profit from the criminal operation being deemed aggravating factors in the case.
Italy's new right-wing government has displayed a harsh attitude towards humanitarian rescue ships that pick up migrants departing Libya in the central Mediterranean Sea. Nevertheless, the majority of migrants arriving in Italy travel along routes from Tunisia.