PARIS, March 5 (UPI) -- Who is this mysterious group that snagged its nickname from a Toulouse petrochemical plant, and that threatens to bomb French targets if its demands are not met?
For three days these questions have haunted France, after the first reports surfaced Wednesday about a shadowy organization calling itself AZF, which has demanded roughly $6 million from the French government -- or else.
Two weeks ago, French officials found and detonated a surprisingly sophisticated bomb placed along the Paris-Toulouse rail line after receiving precise GPS coordinates by AZF directing them to the location. The group has threatened to bomb a dozen rail sites.
But some 10,000 rail workers who scoured 20,000 miles of French rail lines Wednesday and Thursday turned up nothing more. More worrying, officials indicate, AZF has been stonily silent since the first reports of its terrorist threats were splashed across French newspapers this week.
"We are in the presence of people who are very organized, methodical, who constitute a real threat," Le Monde's Friday afternoon's edition reported one police officer saying. "These are also people who are convinced about their capacities, who perhaps have some accounts to settle."
According to the French government and local news reports, the group has made its threats in a series of letters from December to February, along with cryptic messages published in France's leftist Liberation newspaper.
The letters apparently mix scrupulous details -- warning, for example, that the rail bomb would explode 15 minutes after a phone call -- with vague threats.
Besides targeting rail lines, AZF warned, it might also trigger "one or two explosions outside the lines." Those targets, it indicated, would include art works, chemical stations, and public spaces picked for their "great sensitivity and weak protection."
AZF's dialogue with the French government has also been conducted through personal adds placed by the group in France's leftist Liberation newspaper.
"My big wolf, don't take needless risks -- the earlier the better," the group wrote in its first announcement published in the French newspaper Feb. 19. "Give me your instructions."
The add signed itself "Suzy."
The French police "must never lose contact with the adversary," warned former French police commissioner and antiterrorism expert Rene-Georges Querry in an interview published Friday in Le Figaro newspaper.
"This small group cannot be put into a situation of saying that as of now, it will cut off all contact and move to action," added Querry, who describes AZF's actions to date as "a mix of determination and folklore."
French officials acknowledge they have few details about AZF. The group's name mirrors that of a petrochemical plant in Toulouse that explode several days after the Sept. 11, 2001, terrorist attacks in the United States.
But French officials ultimately dismissed mushrooming conspiracy theories of an Islamist attack, attributing the explosion to an industrial accident.
In a Dec. 11 letter, AZF too, described itself as a "secular brotherhood," and earlier this week French Interior Minister Nicolas Sarkozy distanced the likelihood of an "Islamist trail" as investigators scramble to identify the group.
Officials have seized on the few clues offered by the group -- its military references; the GPS coordinates, suggesting an expertise in map making; the relatively modest monetary demands, indicating that AZF may be a small organization.
"From that facts that have been made public, the blackmail practiced by AZF suggests more an affair of common law, even if the anti-institutional tint to its claims might be intriguing," Querry said.
This is hardly the first time France has faced threats from shadowy terrorist entities, including Basque, Corsican and Breton separatist groups.
In 1984, for example, a group calling itself "M5" detonated three bombs in France. It threatened more if the French government did not hand over roughly $5 million. Ultimately, French authorities apprehended the perpetrators -- two petty racketeers.
But the French government -- which already has dispatched an AWACS surveillance flight, according to Liberation -- is taking AZF seriously.
"Certain technical elements lead us to think it might be about people sufficiently dangerous that one must take this affair seriously," French Justice Minister Dominique Perben told RTL radio.
The publication of the AZF threats -- first by the southern French Le Depeche du Midi, and then by national newspapers -- has sparked a separate controversy.
Interior Minister Nicolas Sarkozy blasted Le Depeche for publishing the news -- leaked quietly to the French press on orders of not disseminating it -- as "irresponsible."
"Newspapers don't take their marching orders from the Interior Ministry," retorted Christopher Giesbert, Le Depeche's managing editor.
"It doesn't shock us that the Interior Ministry asked for caution on this subject," said Soria Blatmann, who heads the European desk of Reporters Without Borders. "But reporters are then free to publish the information or not. That's their choice, and that's what happened."