DICKSON, Tenn. — The Dickson County Sheriff’s Office in Middle Tennessee ended up paying a ransom after a malicious computer program blocked access to their files.

Detective Jeff McCliss told WTVF-TV that malware on a computer locked the agency’s case files, which included autopsy reports, witness statements and crime scene photos. He says the malware, called “Cryptowall,” doesn’t tamper with files on a computer, but keeps them locked until a ransom is paid.

After consulting with the Tennessee Bureau of Investigation and the FBI, McCliss said the agency determined the only way to get their files back was to pay the asking price: $500 in bitcoins.

Officials think the malware came from an ad someone in the department clicked on. McCliss says it doesn’t appear that the office was targeted.