Derbyshire police are urging people to take extra safety steps to protect their personal files from computer fraudsters.
The National Fraud Intelligence Bureau has received a number of reports about malicious software known as CryptoLocker.
The virus is mainly spread through emails attachments and can take over personal files such as images and documents.
After the malware scam has been downloaded on to a computer, a pop-up page will launch asking for a payment to remove the software.
Detective Constable Julie Wheeldon, of the East Midlands Fraud and Financial Investigation Unit, said: “Malicious software can be destructive.
“Installing security software on your computer and ensuring that you discard any emails from unknown addresses without opening them are just some of the ways that you can prevent yourself against this type of fraud.”
For advice on how to stay safe when online, visit the Derbyshire police website, www.derbyshire.police.uk, and search for ‘internet safety’.