PARIS -- Gilbert Thiel has been investigating Corsica's vicious feuds for 16 years. As a member of France's team of anti-terrorism magistrates, he knows how hard -- read impossible -- it is to penetrate the island's tightknit criminal world, where nationalism and banditry have blended into a combustible mix.
Mr. Thiel has been giving a lot of interviews recently, ever since a well-known Corsican lawyer was shot and killed in his car Oct. 16. That murder shocked France, coming as an unwanted reminder that Corsica, an island of 305,000 people about 175 kilometers, or 110 miles, off the French coast, is still under the thrall of an old legacy of vengeance and death.
"You think if it's small, it should be easy, but no," said Mr. Thiel, speaking Nov. 15 in his high-security office in the Palace of Justice in Paris. "Everyone is connected. You can't infiltrate, even if you have the right accent and the right complexion."
"The first question they'll ask is which village are you from, and that's it," Mr. Thiel said. "It's over. There were two attempts to infiltrate informants, and it didn't take long for both to turn up dead."
On the morning of Nov. 15, the number of assassinations in Corsica this year stood at 16. By that evening, it had ticked up to 17, with the murder of Jacques Nacer, president of the local Chamber of Commerce and Industry, shot and killed as he was closing up his men's clothing shop in Ajaccio, the island's capital.
"These are assassinations," Mr. Thiel said that morning. "We're not talking about some guy who kills his wife, or a wife who kills her husband. These are settlement of scores among rival bands of organized crime, or fratricidal struggles between nationalist groups."
By one count, there have been 100 assassinations on Corsica since 2008, making the island, per capita, one of the most criminal regions in Europe.
As Mr. Thiel likes to put it, Corsica is a mountain in the middle of the sea, where isolated villages hold onto an ancient culture of vendetta and resist the authority of the French government.
Now 64, a year away from retirement, Mr. Thiel enjoys a reputation as a free-speaking voice in an often starchy French judiciary. He is the author of several books, of which the most unusual was a comic book that mocked someone who looked suspiciously like former President Nicolas Sarkozy.
Since mid-October, he has spoken out against the French government's lack of a consistent response to the violence in Corsica. He has cited a series of amnesties in the 1980s that were followed by other halting initiatives. He has criticized a flawed reform of intelligence-gathering that he said had led to confusion, and few results.
It is no wonder that Corsican society today is paralyzed by fear, he said. "How can a population rebel against this kind of violence when the state apparatus is seen to be underperforming?"
That "code of silence" was vividly confirmed last week by France's top security official, Interior Minister Manuel Valls, who said on national television that he had been stunned by the reticence of people on the streets of Ajaccio. "I saw fear on their faces," he said. "Some didn't dare talk to the minister of the interior."
Crime in Corsica has evolved since 1998, when, in a stunning act of political terrorism, France's top government official in Corsica -- the prefect Claude Érignac -- was gunned down. Mr. Thiel was the investigating magistrate in the case, in which Yvan Colonna was eventually convicted of the murder.
In the meantime, the separatist movement splintered, as rival gangs began to compete over the weapons trade, money laundering and the levy of a so-called revolutionary tax.
It did not take long for the means to overwhelm the ends. Collecting taxes for the armed struggle became racketeering; the weapons trade became a lucrative business, as did gambling, real estate and the competition for public contracts.
The "barons" of the movement began to look for their share.
"It's like politicians who collect money for their party," Mr. Thiel said. "Bit by bit, they begin to take a little pinch for themselves. It all goes through the same pipeline. That is the characteristic of dirty money."
The last two murders in Corsica are unlikely to be characterized as terrorist acts, although the Oct. 16 death of Antoine Sollacaro, who had been Mr. Colonna's defense lawyer, was seen by some as a symbolic attack. But as Mr. Thiel cautioned, it is important to determine whether he was killed "because he was a lawyer, or while he was lawyer."
Mr. Thiel's last big Corsican case involved a number of young thugs, arrested for a series of violent acts committed in 2007 and 2008, including the tossing of a grenade into a police station.
He compared the defendants, who were convicted and sentenced last July, to "children soldiers," who turned to crime as much for the money and the thrill as for the politics. "If you ask them, they'll say they're doing it for Corsica, but they can't say much beyond that," he said.
This article originally appeared in The New York Times.