He Saved 31 People at Sea. Then Got a 142-Year Prison Sentence.

In the same Chios prison as Mr. Mohammad are two Afghan men, aged 24 and 26, both of whom received 50-year sentences for facilitating illegal entry into Greece on sea voyages last fall, according to to Lorraine Leete of the Legal Centre Lesvos, which represented them. One had traveled with his pregnant wife and child.

And a 28-year-old Syrian man is in prison in Athens after receiving a 52-year term in April after crossing from Turkey with his wife and three children, according to his lawyers, Vicky Angelidou and Vassilis Psomos.

The lawyers, who declined to name those convicted on privacy grounds, said there was no evidence that they were driving the boats and that there was only one witness, a Greek Coast Guard official.

Mr. Mohammad’s sentence was heavier because two women drowned in that crossing. But eight migrants who had been on the boat said that the Turkish smuggler transporting them had abandoned the vessel and that Mr. Mohammad tried to save it after a Turkish Coast Guard vessel forced it into Greek waters, according to his lawyers. Only two of the migrants were allowed to testify in court because of coronavirus restrictions.

“The criminalization of migrants as a means of deterrence has been a strategy for a long time,” said François Crépeau, an expert on international law and a former top United Nations official on the rights of migrants. “The latest step is what we’ve seen in Greece recently, which is obscene numbers of years in prison for people who are basically trying to save their lives and protect their families.”

Over the past two years, smugglers have been increasingly limiting the time they spend on boats, abandoning migrants when they approach Greek waters, or training them to take the wheel, according to Dimitris Choulis and Alexandros Georgoulis, the lawyers defending Mr. Mohammad and others in similar predicaments.

When boats arrive on Greek shores, one migrant is typically singled out by officials, Mr. Choulis said. But the decision is often made without real evidence, he added, noting that one Afghan man is facing smuggling charges simply for having the GPS open on his cellphone during a crossing.