Captain Marc Reig does not look like a man at the centre of a storm. But that is what he is, despite the fact that his ship, the migrant-rescue boat the Open Arms, is safely moored in the pretty port of Pozzallo in southern Sicily, its peace disturbed only by the waves gently lapping against its hull.

When the ship, operated by the Spanish charity Proactiva Open Arms, lifted 218 desperate migrants from the leaky raft on which they had been trying to cross the rough seas of the Mediterranean last week, it seemed like a routine operation. In the last three years, more than 5,000 migrants have crossed the Mediterranean onboard the ship run by the NGO, which patrols an area outside Libyan waters. But what happened next was anything but routine. As the ship docked in Pozzallo, dozens of police closed in.

As soon as the human cargo disembarked, the ship was seized and three members of its crew put under investigation. The chief prosecutor of Catania, Carmelo Zuccaro, has accused them of refusing to hand the migrants over to Libyan coastguards, and so enabling illegal immigration. The 37-metre boat has remained moored in Pozzallo, awaiting a judge’s verdict on its fate, while Italians who no longer want their country to provide a refuge to migrants are celebrating its seizure.

The Proactiva ship seems to have become a political hostage in a country where immigrants are perceived by many as invaders and parasites, and where the issue of migration has become toxic in the wake of this month’s election, which saw a surge in support for anti-immigrant parties.

On 3 February, a neo-fascist shot and injured six Africans in the city of Macerata, and a few days later, rightwing parties vowed to kick 600,000 migrants out of the country if elected. In this context, anyone who helps migrants is considered an enemy, responsible for helping human traffickers.

Anabel Montes was the mission chief for the Open Arms rescue. Photograph: Alessio Mamo

This is the crime of which the Spanish captain of the Open Arms is accused. Of his 19 crew members, more than half have returned home. Reig, 42, who now spends most of the time locked in his cabin, is haunted by the events of that dramatic night a week ago, when his ship picked up the migrants from their raft – and immediately faced a challenge from Libyan coastguards, who he says threatened to kill the crew if they didn’t hand the migrants over.

“It all happened in the space of a few minutes. We had just rescued 218 people, when we saw the Libyan coastguard ship arrive,” he tells the Observer. “They said we had to give them back the migrants, or they would shoot us.”

The Italian authorities called the Open Arms’ crew and advised them to leave the migrants to the Libyans, because they said Tripoli was in charge of the save-and-rescue zone in that area of the sea. But Reig says this is not true – the Libyan SAR zone was unilaterally declared by Italy and Libya around Christmas, but a notification by the IMO (International Maritime Organisation) has not been issued. Moreover, the rescue took place in international waters and so the orders of the Libyan coastguard were not binding. The law of the sea is clear: the responsibility lies with whoever rescues the boat first. “At that precise moment I thought about the dozens of empty boats we found at sea in recent months,” says Reig. “The migrants who were on board had been captured by the Libyans and deported back to Tripoli. The refugees we saved spoke of unimaginable torture. They say they would rather die than go back to Libya.’’

With Libyan rifles still pointed at his crew, Reig turned north towards Sicily. “If we had abandoned them to the Libyans, we would never have forgiven ourselves,’’ says Anabel Montes, coordinator of the rescue mission.

“We were victims of an armed attack, but we are the ones on trial,” says Riccardo Gatti, head of the Open Arms mission. “And all this happens a week after the elections and the triumph of the rightwing parties in Italy. It does not seem a mere coincidence.’’

The morning after the standoff, Matteo Salvini, leader of the far-right Northern League, tweeted: “Finally an Italian prosecutor is blocking the human trafficking.”

Salvini, who ran an election campaign promising tougher laws against migrants, won almost 18% of the vote, becoming the undisputed leader of the centre-right. But Italy’s intolerant attitude began way before his rise.

After the shipwreck of 3 October 2013, when 368 people died after a fire broke out on their boat a few miles off the Italian island of Lampedusa, Italy declared war on human traffickers. The goal was to capture the smugglers who organise the crossings and protect the migrants.

This is how the year-long naval and air operation Mare Nostrum was born. During the mission, 150,000 migrants arrived safely in Italy, before moving on to destinations across Europe. Unfortunately, the operation angered some countries, above all France, Austria and Switzerland, who began to repel migrants and return them to the Italian authorities. The refugees rescued at sea found themselves stuck in Italy, and reception centres from north to south began collapsing. Italians started to complain about the thousands of migrants trapped in their cities.

“In 2015, Italy’s approach starts to change,” explains Fulvio Vassallo, asylum law expert at the University of Palermo. “The Mare Nostrum operation was replaced by the more authoritarian Frontex, whose main objective is not saving lives but border control. The hunt for human traffickers began to lose its humanitarian purpose, replaced by feelings of intolerance.”

In short, human traffickers had to be captured, not to put an end to the abuses perpetrated on refugees, but to stop the flow of people. Charity boats continued to run sea rescues, and picked up more than a third of all migrants brought ashore in 2017, compared with less than 1% in 2014. But then Italy’s minister of the interior, Marco Minniti, fearing that the NGOs were helping people smugglers from North Africa, proposed a code of conduct for the charities, including the commitment to take armed police officers onboard, which many considered unethical.

“The message was clear,” says Vassallo. “NGOs had become a problem for European countries. [They] not only continued to deliver migrants, but also witnessed the injustices perpetrated by Libyan authorities. Linking them to the traffickers was a pretext to get rid of them.”

Last August, Italian police impounded the Iuventa, a boat operated by German NGO Jugend Rettet, and dispatched a navy patrol boat to Libya as part of an attempt to end the refugee crisis. According to a police statement “the Iuventa was used for activities facilitating illegal immigration”. The ongoing investigation has found no real evidence against the NGO. But since then, charity efforts to save lives at sea have become increasingly difficult. Five aid groups that operate migrant-rescue boats in the Mediterranean have refused to sign up to the Italian government’s code of conduct, but three others have backed the new rules. Among those three is Proactiva Open Arms, which has seen donations fall by 40% in the last year.

But if one part of Italy rejoices at the boat’s seizure, another celebrates the deeds of Captain Reig, sending him messages of support. But he rejects any description of himself as a hero. ‘‘The real heroes are those who cross the desert for years, enduring torture and persecution,” he says. “Those who, in order to get to Europe and not go back to Libya, throw themselves into a sea in which they cannot even swim.”