In three-and-a-half years as chief prosecutor in the Sicilian city of Catania, Giovanni Salvi has ordered the arrest of dozens of people smugglers -- but none of them has been alleged to have as much blood on their hands as Mohammed Ali Malek, the Tunisian captain of the recklessly overcrowded boat that capisized and sank off Libya on the night of April 18t/19th.
Hundreds of the victims were locked in the hold, their panicked reactions having contributed to the vessel toppling over following a collision with a merchant ship sent to its aid.
Having seen photographs of the inside of the sunken wreck Salvi has no doubt that the scale of the disaster was as great as depicted by the 24 migrants who survived.
"We will never know the exact number but I fear we will be in a position to confirm a death toll close to 800," the 63-year-old veteran of Sicily's battles with the mafia told AFP in an interview.
And it could have been much worse. "There were supposed to be 1,200 people on the boat but after having stuffed everyone into every possible corner, they literally could not get anyone else onboard before they left Libya," Salvi said.
The prosecutor's examination of events on that fateful night was now complete and he said a decision would be made soon on whether Malek, 27, would stand trial on charges of culpable homicide, causing a shipwreck, confinement of human beings and collusion in illegal immigration.
A Syrian who is alleged to have served as first mate on the boat is also in custody awaiting possible trial on lesser charges.
The wreck was the third significant disaster of its kind that has landed on Salvi's desk as the migrant flux from North Africa has reached unprecedented proportions in the last 18 months.
More than 200,000 people have landed at Italy's ports since the start of 2014 and more than 5,000 have perished in the attempt to get there.
The first two major wrecks were easier to deal with because the boats had left from Egypt, where Italy's judiciary can count on good cooperation with the local authorities.
"Three traffickers we believe to be the bosses of the criminal gang behind these (first two) wrecks were arrested," Salvi said.
"But in Libya there is no authority to cooperate with."
Salvi describes the smugglers as well-organized but discounts suggestions they form a single network or that they are working hand-in-hand with Italian organized crime.
Traffickers dealing with refugees from Syria, Eritrea and Somalia often offer a made-to-measure travel service designed to get the client to their desired final destination.
Their business depends on trust but they can also be ruthless when required: in Catania last year, smugglers abducted ten migrant youths as part of a ploy to ensure their relatives met agreed payments for their trips.
Although he acknowledges there is no easy solution to the current crisis, Salvi is hopeful that a new European Commission plan to distribute asylum-seekers more evenly between most EU countries will help to reduce the level of clandestine immigration.
Many migrants arriving in Italy are desperate not to be registered here as they want to travel further north, either because they have family connections or because they want to make their first initial request for asylum in countries such as Germany, which takes the most refugees in absolute numbers, or Sweden, which takes the most in relation to its existing population.
"This is a very dangerous situation for Europe because it pushes underground people who could stay in legal channels," Salvi said.
The experienced lawyer is less positive about European plans to try and destroy boats used or potentially used by traffickers.
"That is not going to resolve the problem," he said, arguing that it would risk destroying the livelihood of Libyan fishermen and causing a backlash against Europe.
"Some say we will get better results by refusing to help the migrants, but even death will not deter people fleeing war and persecution."