The research material pertained to 658 cases among which a few concerned crimes against systems, data and computer programmes (39, i.e. 6,0% of all cases). A vast majority of cases concerned traditional offences committed through the use of the Internet (619, i.e. 94,0% of all cases). Among common offences frauds were predominant (79,6%), where modus operandi pertained to offering various goods during auctions being organised via the Internet.