It is claimed that Shiina faked the sender information on the e-mails in an attempt to avoid detection, breaking Japanese laws.
"Spammers believe they can escape the long arm of the law by hiding on the Internet, but increasingly the authorities are cracking down on this kind of net abuse. No-one who hears about a single person believed to have sent 2.2 billion spam e-mails can be in any doubt as to the scale of the problem, and it's essential for a clear message to be sent out that the police are serious about catching the criminals responsible," said Graham Cluley, senior technology consultant for Sophos. "Legitimate businesses need to make sure that they are abiding by the law, and be careful not to hire firms and third-party individuals to market their Web sites or goods via junk e-mail."
Last month, in a separate case, the first arrest in Japan of a malware author was made. Kyoto police uncovered a plot to infect users of the P2P file-sharing network Winny with a Trojan horse that displayed images of popular anime characters while wiping music and movie files.