Prince George RCMP are advising local people that they're targets of a scam when they receive pop-up messages saying their computer has been frozen by police for a criminal investigation .

In some cases the message provides a list of possible offences, while in other cases the pop-up may list a specific offence such as "child pornography" or "illegal music downloading".

The message then tells recipients to pay $100 via a payment service provider so their computers can be unlocked but it won't happen, Prince George RCMP Cpl. Craig Douglass said Wednesday.

The messages claim to come from the RCMP or other agencies but they do not, Douglass said, and added the messages are a scam and the computer has likely been infected with a virus.

"These types of messages, commonly known as 'ransomware' or 'scareware,' are designed to create such shock and anxiety that victims respond by sending money quickly," Douglass said. "Your computer will not be unlocked if you pay the money and you will never get your money back."

Douglass provided some tips for dealing with such situations:

- Never click on a pop up that claims your computer has a virus;

- Update your anti-virus software often and scan your computer for viruses regularly;

- Don't click on links or attachments in e-mails sent to you by someone you don't know

- Turn on your browser's pop-up blocking feature

- Never download anti-virus software from a pop-up or link sent to you in an e-mail.