Police in Tokyo have arrested 25-year-old Yuki Shiina following a complaint last year by an ISP that he was sending huge numbers of spam emails that advertised gambling and dating Websites.

According to a report from security vendor Sophos, authorities believe that Shiina bought 600,000 email addresses off the Internet for 100,000 yen (US $927) and earned over 2 million yen (US $18,540) through the spam campaign.

Shiina allegedly faked the sender information on the emails in an attempt to avoid detection, breaking Japanese laws. He is believed to have sent some 2.2 billion messages.

"No one who hears about a single person believed to have sent 2.2 billion spam emails 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.

— Tim Wilson, Site Editor, Dark Reading