The number of Internet-related criminal cases in which arrests were made totaled 201 in the first six months of this year, compared with 247 cases in all of 1999, according to a National Police Agency survey released Thursday.
Among the 201 cases in the January-June period, there were 25 cases of fraud relating to Internet transactions, including Internet auctions, the survey showed.
In each of the Internet auction cases, an average of about 20 people were cheated out of some 100,000 yen each, NPA officials said.
The number of cases in which the law banning child prostitution and child pornography was violated, including the arranging of paid sex with minors and the publication of obscene pictures of high school girls on the Internet, totaled 50.
There were nine such cases in the two months after the law came into force in November 1999.
Other examples of cyber-crime include the distribution of obscene materials, numbering 64 cases, defamation, at 13, and copyright violations, at 12, the survey said.
No arrests were made over illegal activities by hackers, despite a number of intrusions on government Web sites earlier this year.
Eight cases of people using other people's passwords to illegally access computers were reported, it said.
The NPA said the total number of computer-related criminal cases, including the illegal manipulation of online banking networks, was 234 in the six-month period. There were 357 such cases last year.