The Tewksbury Police Department paid a ransom of $500 in bitcoin to criminals who encrypted the data on their computer.

The police computer network was infected by Cryptolocker, a type of malicious software, in December. The system was down for several days as the malware traveled through the Officer In Charge’s computer to the largest database, which held files that included arrest logs, motor vehicle records, calls, and other records, according to the Town Crier. The back-up was corrupted too, so police officers were forced to pay the ransom requested in a message that appeared on the screen:

“Your personal files are encrypted,” it read. “File decryption costs ~ $500. If you really value your data, then we suggest you do not waste valuable time searching for other solutions because they do not exist.”

The address to send bitcoins to could not be traced  by authorities including the FBI and National Security Agency.

Police Chief Timothy Sheehan told the Town Crier: “We did everything we possibly could. It was an eye opening experience, I can tell you right now. It made you feel that you lost control of everything. Paying the bitcoin ransom was the last resort.”

This is not the first time police computers have been attacked by hackers who force them to pay bitcoin ransom. CoinFox wrote earlier about a Chicago police department that reportedly transferred $606 in bitcoins to criminals to get back access to data on their computer. In November 2014, the sheriff's office in Tennessee paid $572 in bitcoins to a hacker known as Nimrod Gruber to regain access to its files. A New Jersey school district computer network was hacked last month by criminals who requested 500 BTC as ransom.