According to the National Bureau of Investigation, swindlers ordered rooms and meeting facilities via e-mail. Mobile phones and portable computers were also requested for bogus participants.
Fax copies of credit cards were sent to the hotels in lieu of payment for goods and services. However, the cards turned out to be stolen.
The police say many incidents have occured with false messages arriving from France, Canada and African countries.
In one case the swindle almost succeeded as the hotel had already acquired the requested products before the fraud was discovered.
Another fraudster had requested that mobile phones be sent to a French address before the event.
YLE24