Personal information on as many as 10,000 convicts has been leaked over the Internet from a prison officer's computer infected with a virus, Justice Ministry officials said Monday.
The information includes names of prisoners in Kagoshima and Shiga prefectures and inmates of a detention house in the city of Fukuoka, as well as the cases they were involved in, the ministry's Correction Bureau and other sources said.
The information was initially stored on a CD by a staff member at Kagoshima Prison and handed to a staff member of Kyoto Prison in December.
That employee left the CD in a personal computer. The data was leaked after the computer was infected with a virus via the peer-to-peer file-sharing program Winny, which had been installed on the computer, the officials said.
The ministry was notified of the information leak on Feb. 3.
It is now investigating the way prison staff exchange information, the officials said.
A number of information leaks involving Winny software, which enables the transfer of files over the Internet, have been reported recently.