By Joseph Menn
SAN FRANCISCO (Reuters) - A Russian man charged by U.S. authorities on Monday with controlling a hacking gang that locked up hundreds of thousands of computers to steal banking credentials and commit cyber extortion claimed in online chats to have written one of the most effective pieces of malicious software ever detected, according to an FBI affidavit.
In electronic conversations recovered by the FBI, someone using nicknames the FBI associated with the Russian suspect, Evgeniy Bogachev, told associates that he had written the credential-stealing software Zeus.
Writing malicious software is not a crime in the United States. Bogachev was charged with controlling one network of compromised computers that used a variant of Zeus, known as GameoverZeus, and with installing the "ransomware" known as Cryptolocker on some of those machines.
(Reporting by Joseph Menn; Editing by Tom Brown)