DOUBLE JEOPARDY

In his mid-forties, Lingel had an unconventional history. He was born in Windhoek, the capital of Namibia, which, as South-West Africa, had been one of the few outposts of imperial Germany during the colonial period. As a five-year-old he then moved with his parents to Cape Town, so he grew up speaking fluent English as well as German. He returned to his parents' homeland to study, and after graduating joined the police. Here he progressed well through the ranks of the motorway force, while never finding the work particularly challenging.

As an amateur geek, he leaped at the chance to apply for a post in the Baden-Württemberg police in 2001. The Stuttgart headquarters needed somebody with experience of the open-source operating system Linux, to provide network security. Five years later he was permitted to migrate with his computer skills to the criminal-investigations department, where he was assigned to work under Frank Eissmann.

Matrix001 was not the only German identified by Keith Mularski as an active member of DarkMarket. The other two were Soulfly, real name Michael Artamonow, and Fake, real name Bilge Ülusoy. Initially, the State Prosecutor sought to indict Matrix001 on charges of forming a criminal conspiracy, but this required proof that he was working in cahoots with the other two.

For some reason, however, no investigation was ever launched into Fake and Soulfly, and this was partly responsible for a judge in October 2007 forcing the State Prosecutor to drop the accusation of conspiracy in favour of the lesser charges of credit-card fraud. Why they dropped the investigation into the presumed co-conspirators was just the first of several unanswered questions, which were to undermine confidence in the ability of the Provincial and Federal Police in Germany to investigate the case.

And the Baden-Württemberg police in Stuttgart had a lot riding on the investigation into Matrix001. Usually all communication in international cases like this would be filtered through Wiesbaden, but the chief investigator, Frank Eissmann, had persuaded his superiors that he should be allowed to talk directly to Keith Mularski, the FBI's key man.

There were thus jitters aplenty when Mularski heard from Matrix001 that the German hacker had received a message from an anonymous hushmail account warning him that he was about to be busted. And police in London, Pittsburgh and Stuttgart were all praying that the source was not too close to their own home.