MOSCOW — On the Internet, he was known as BadB, a disembodied criminal flitting from one server to another selling stolen credit card numbers despite being pursued by the United States Secret Service.

And in real life, he was nearly as untouchable — because he lived in Russia.

BadB’s real name is Vladislav A. Horohorin, according to a statement released last week by the United States Justice Department, and he was a resident of Moscow before his arrest by the police in France during a trip to that country earlier this month.

He is expected to appear soon before a French court that will decide on his potential extradition to the United States, where Mr. Horohorin could face up to 12 years in prison and a fine of $500,000 if he is convicted on charges of fraud and identity theft. For at least nine months, however, he lived openly in Moscow as one of the world’s most wanted computer criminals.

The seizing of BadB provides a lens onto the shadowy world of Russian hackers, the often well-educated and sometimes darkly ingenious programmers who pose a recognized security threat to online commerce — besides being global spam nuisances — who often seem to operate with relative impunity.