Second of two articles

The French cargo ship Ville de Virgo was already running a day late when it steamed into Hamburg harbor on April 3, its stadium-size deck stacked 50 feet high with cargo containers bound for Asia.

At the dock, harried German customs agents skimmed quickly through a fat manifest that included the usual Asia-bound staples -- fertilizer, bulk chemicals, cheeses. A last-minute addition, 214 ultra-strong aluminum pipes purchased by China's Shenyang Aircraft Corp., was one of the final items cleared before the 40,000-ton ship fired its engines again and headed to Asia.

But within hours after the ship departed, the story of the manifest began to unravel. German intelligence officials discovered that the aluminum was destined not for China but for North Korea. The intended use of the pipes, they concluded, was not aircraft production, but the making of nuclear weapons.

On April 12, in a dramatic but little-noticed intervention, French and German authorities tracked the ship to the eastern Mediterranean and seized the pipes. German police arrested the owner of a small export company and uncovered a broader scheme to acquire as many as 2,000 such pipes. That much aluminum in North Korean hands, investigators concluded, could have yielded as many as 3,500 gas centrifuges for enriching uranium.

"The intentions were clearly nuclear," said a Western diplomat familiar with the investigation. "The result could have been several bombs' worth of weapons-grade uranium in a year."

The voyage and capture of the Ville de Virgo exposed one of the most ambitious attempts yet by North Korea to obtain materials for building nuclear weapons. But the episode also offers a glimpse into the shadowy world of weapons proliferation, in which missile parts and bomb materials circle the globe undetected, secreted away in cargo containers and suitcases, concealed by phony ship manifests and fictitious company names, eluding customs agents and defying international treaties.

The story of the Ville de Virgo is a case study in the workings of the gray zone, a combination of weak states, open borders, lack of controls and a ready market of buyers and sellers for weapons of mass destruction.

The attempt to import the aluminum tubes is being closely studied by intelligence agencies for possible clues about the design and origins of North Korea's uranium enrichment program. In January, North Korea announced that it was withdrawing from the international treaty that bars it from making nuclear weapons, and the country is believed by intelligence agencies to be pursuing nuclear weapons through two different routes -- bombs based on uranium and those based on plutonium.

In recent months, North Korea's attempts to seek parts and technology in Europe have increased dramatically, U.S. and European intelligence officials say. Lately, they say, the attempts are becoming ever more elaborately disguised.

On April 4, just one day after the Ville de Virgo left Hamburg, a different cargo ship departed Japan's Kobe Harbor carrying three devices known as direct-current stabilizers, which also are used in uranium enrichment, according to a Japanese government account of the incident. Just as with the aluminum shipment, the electronic parts were being routed to a third country -- in this case, Thailand -- where the cargo would be diverted to North Korea.

In mid-May, a month after the aluminum pipes were seized, North Korea nearly succeeded in acquiring 33 tons of sodium cyanide, a chemical used in making the deadly nerve agent tabun, according to Western diplomatic sources. The chemicals were purchased legally from a German manufacturer who believed the buyer was a Singapore company. But in fact, a switch was planned that would have diverted them to Pyongyang, the North Korean capital.

Both efforts were thwarted, but intelligence officials have little doubt that others succeeded. "There are countries in the world where you can pay $2,000 to a government minister and he'll sign anything -- and then confirm to you that he signed it," said Rastislav Kacer, a former Slovak deputy defense minister who helped lead an investigation into a similar attempt by North Korea to buy sophisticated radar equipment. "Documents that are fake can be made to appear very real."

In such an environment, said Kacer, now his country's ambassador in Washington, "no system is ever 100 percent leak-proof."

Special Aluminum Tubes

The French-owned Ville de Virgo is a workhorse of the modern shipping trade, a floating warehouse that moves cargo along a circuit running from Hamburg and Rotterdam to Singapore and Pusan, South Korea. At each port, goods are brought to the ship in pre-packed steel containers, which are then stacked five high on the top deck. Only rarely are the containers opened and physically searched.

On the morning of April 3, the Ville de Virgo was running a day behind schedule as it took on freight and awaited paperwork in Hamburg before setting off on a nine-week, round-trip voyage to China and Korea. Local customs agents had visited the ship dozens of times in the past, and on this day, German officials say, there was nothing outwardly unusual about the ship or its cargo.

But one container on the deck held aluminum tubes, and German intelligence officials had been watching these very pipes for months.

Measuring nearly eight feet in length and nine inches in diameter, the tubes were made of a special alloy, 6061-T6, known to be both light and exceptionally strong. Similar tubes are used in a wide range of commercial products, from bicycle frames to aircraft parts. But they also are useful in the construction of machines known as gas centrifuges, which enrich uranium into the key material for nuclear weapons.

Throughout the second half of 2002, intelligence agencies in the United States and Western Europe picked up multiple signals that North Korea was attempting to acquire such tubes, along with other specialized metals used in centrifuges, U.S. and European sources say. Germany's top nonproliferation agency issued a warning in the fall that North Korean agents were known to be "obtaining sensitive goods" by using front companies or third countries as cover. Intelligence reports suggested that a large quantity of pipes -- perhaps 220 tons or more -- was being sought across Europe. The tubes are of a different type of aluminum than those that figured prominently in suspicions about Iraq.

Despite the increased vigilance, North Korea may have already succeeded in acquiring hundreds of such tubes, using connections and routes developed over years. "All they need is help from one company -- perhaps a small company, one that may never actually see the aluminum pipes, or have them in their hands," said Eckhard Maak, a government prosecutor in Stuttgart, Germany, who helped investigate the case. "With only a phone and an Internet connection, you can send such materials across the world."

Export License Denied

The unlikely supplier of the aluminum pipes was a tiny German export company called Optronic. Its owner, Hans Werner Truppel, made a living brokering sales of optical and electronic equipment out of his house, a modest one-story dwelling in a village 85 miles northwest of Munich.

Three years ago, German law enforcement officials say, Truppel struck up a relationship with a North Korean businessman who claimed to represent an import-export company, Nam Chon Gang. At first, the North Korean company asked for help from Optronic in obtaining obscure machine parts and electronics, offering cash in payment. Truppel sold the firm vacuum pumps and machines known as angle grinders, in each case with the approval of German customs.

Then, last fall, Nam Chon Gang approached Optronic with a new wish list: Could Truppel find a supply of aluminum pipes, made of a specific alloy and cut to precise dimensions? In this case, the North Korean businessman claimed to be brokering a deal on behalf of Shenyang Aircraft Corp., one of China's top aircraft manufacturers. Later, a letter bearing Shenyang's logo vouched for the purchase, according to a law enforcement official who has seen the document. The letter said the aluminum was to be converted into airplane fuel tanks.

It all seemed legitimate, according to Truppel's Frankfurt attorney, Egon Geiss. In September, Optronic located British-made aluminum pipes at a company in nearby Ulm, Germany, and paid the equivalent of just over $80,000 for 214 of them. Truppel then began the process of securing the needed export papers.

To Truppel's surprise, the German government balked. Officials in the Trade Ministry, aware of the potential uses for such tubes, looked closely at Optronic's application and began picking it apart. The story about aircraft fuel tanks was dismissed as "not plausible," according to Maak, the prosecutor. Moreover, German officials were skeptical that a major Chinese aircraft corporation would employ an unknown North Korean firm to do its shopping.

"Why the North Korean middleman?" Maak said he wondered. "It seemed highly unusual."

The denial left Truppel baffled and financially exposed, according to Geiss. Now the businessman was stuck with 22 tons of aluminum, which he had paid for but couldn't use. Through the fall and winter, he tried to unsuccessfully sell the pipes to others at a discount. Meanwhile, the Ulm company that had sold the pipes to Truppel in September was still holding them in its warehouse and was pressuring Truppel to pick them up.

Exactly how and why the pipes ended up on the Ville de Virgo remains in dispute. Geiss said Truppel received a call from Delta-Trading, a relatively small metals production, distribution and export firm based in Hamburg. Delta offered to take the pipes and promised to secure the necessary export papers, he said. Truppel "explained to Delta in writing that he was unable to export" the pipes, Geiss added. But in the end Truppel agreed to pay Delta about $6,000 -- roughly half the profit he had expected to make on the deal -- to take the matter off his hands.

"He assumed that Delta, because of its connections, had other legal avenues for exporting the aluminum," Geiss said of Truppel. "He understood that Delta was to take care of all the necessary arrangements." Delta declined comment.

German prosecutors say Truppel was not so naive. "He definitely knew what he was doing," Maak said. "The important thing is, Optronic was denied permission to export, and it did so anyway."

German officials were wary enough to issue a warning urging customs agents to watch for outbound shipments of aluminum pipes. Sometime after April 4 came a report that 22 tons of aluminum had moved from Ulm to Hamburg to be loaded onto the Ville de Virgo.

By the time the warning was issued, the ship and cargo were already on their way to the Mediterranean.

A Trove of Evidence

The North Korean man who drew Truppel into the aluminum scheme has never been publicly identified. But German and U.S. investigators say companies like Nam Chon Gang exist in cities throughout Europe, Japan and other regions that offer access to critical technology.

Last August, police made a rare move against such a company in Bratislava, the Slovak capital. The company, New World Trading Slovakia, was founded in March 2001 by two North Koreans who apparently were seeking a quiet location for negotiating deals with customers on three continents, Slovak officials say.

One of them, Kim Kum Jin, 51, had once served as an economic adviser at North Korea's embassy in Egypt. Kim and his partner, Sun Hui Ri, 48, quickly grew fond of their new home. They bought a Mercedes-Benz and opened shop in a luxurious high-rise in one of Bratislava's newest commercial districts, police investigators said in interviews in the Slovak capital. The couple even listed their company in the city's business registry.

But last summer, Slovak federal police, after months of surveillance, began to suspect the two were trading in weapons technology. Lacking sufficient evidence to file charges, the authorities ordered the couple to leave the country last August.

Kim and Sun left behind a trove of documents, police said, including financial records, invoices and bills of lading. The papers described multiple deals by the pair to procure materials for weapons programs, as well as millions of dollars in sales of missile technology to Egypt, Libya, Iran, Syria and Vietnam. One of their major clients, documents revealed, was an Egyptian military-industrial concern.

"They did it all by fax and computer," said an investigator with firsthand knowledge of the case, who spoke on the condition his name not be used. "None of the material ever crossed into Slovakia, which would have been a clear violation of the law. That's why they were able to operate as long as they did."

This pattern is at the heart of how governments such as North Korea manage to traffic in weapons materials. Many countries have agreed to treaties and multilateral agreements, such as the nuclear Non-Proliferation Treaty and the Missile Technology Control Regime, in an effort to restrict such dangerous transfers. But these efforts were defeated by North Korea using faxes and computers. North Korea has said it does not accept the treaties and defended its right to sell weapons abroad.

"With North Korea you have a strange mix of impressive, extensively clandestine systems and sometimes incredible naivete about how things work," said Greg Thielmann, recently retired director of the office on strategic, proliferation and military issues at the State Department's Bureau of Intelligence and Research. "But somehow they have found a way to operate in a world of export-control regimes and still buy the things they need, and still ship their missiles to other countries."

Logistical support along the way is provided by North Korea's embassies and staff, whose activities and travel are protected under the rules of diplomacy, U.S. and European intelligence officials say. Backing for complex weapons deals comes from North Korean banks, including the Vienna-based Golden Star Bank, Pyongyang's only financial institution in Europe. The imposing red stucco building near one of Vienna's busiest markets has no customers and no private accounts, yet its activities have raised alarms within Austria's Interior Ministry.

A report by the ministry's office for the protection of the constitution included a list of activities the agency had connected to the bank. It included intelligence-gathering as well as "money-laundering, the distribution of forged currency and illegal trade with radioactive substances."

Unscheduled Stop

French and German officials had little evidence in hand on April 10 when they pondered their options for dealing with the Ville de Virgo. By this time, the ship was in the eastern Mediterranean, far beyond the territorial reach of the two countries, steaming southeast toward the Suez Canal at 23 knots.

One possible solution -- letting the ship proceed to an Asian port and working through the host government -- was ruled out as too risky. Another option, since the ship was French-owned and technically under France's jurisdiction, was to stop the ship at sea and transfer the cargo to a French military vessel.

Instead, it was decided that the aluminum pipes simply should be removed, quickly and quietly, at the first possible port. The ship's French owner endorsed the plan.

When contacted by radio, the Ville de Virgo's captain was unaware of any controversy involving the aluminum tubes. But he agreed to a request to make an unscheduled stop in the Egyptian port of Alexandria, just outside the Suez, to remove the tubes from his ship. As the ship arrived in Alexandria on April 12, a special crew and cargo crane were waiting at the dock. Another vessel returned the tubes to Hamburg on April 28.

In Stuttgart, Truppel, the Optronic chief, was arrested for violating German export laws and was ordered held without bail. He remains imprisoned in Stuttgart awaiting trial. The company that acted as an export middleman, Delta-Trading, has not been charged. Geiss, Truppel's attorney, plans to argue that his client was tricked by Delta and North Korea.

Back at Hamburg's harbor, the watch for aluminum tubes continues. Nam Chon Gang and its mysterious North Korean entrepreneur, thwarted in one attempt to obtain the metal, might be trying again: U.S. proliferation officials said they learned from European allies of "multiple" efforts to acquire aluminum tubes in recent months.

The dimensions of the tubes suggest to nuclear experts that North Korea is attempting to build a type of gas centrifuge designed by the European consortium Urenco -- a design stolen by Pakistani scientists in the 1970s. The Urenco centrifuge uses an aluminum casing that is roughly the same size as the tubes exported by Optronic, said David Albright, a physicist and president of the Washington-based Institute for Science and International Security.

But it takes more than aluminum to build a centrifuge, Albright noted. Highly specialized magnets, bearings and a metal known as maraging steel are also required. North Korea would probably have to import all those things, yet there have been no known interceptions of such materials.

"There would have to be many more shipments," Albright said. "Usually what you see is only the tip of the iceberg."

Stopping a single shipment of aluminum tubes from reaching North Korea was a setback for Pyongyang -- but probably only a temporary one, he said. "You can hurt them badly," Albright said, "but in the end you can only delay them from succeeding."

Special correspondent Shannon Smiley in Berlin and researcher Robert E. Thomason in Washington contributed to this report.

The Ville de Virgo, shown in November, was used in an apparent scheme by North Korea to obtain materials for making nuclear weapons. French and German authorities foiled the effort in April.