Lost evidence includes all body camera video , some in-car video , some in-house surveillance video , some photographs , and all Microsoft Office documents . Data from that period backed up on DVDs and CDs remained intact . While archived data has its importance , more worrying is that the department lost data from ongoing investigations . In an interview with WFAA , who broke the story , Stephen Barlag , Cockrell Hill 's police chief , said that none of the lost data was critical . The department also notified the Dallas County District Attorney 's office of the incident . The department says the infection was discovered on December 12 , last year , and the crooks asked for Attack.Ransom a $ 4,000 ransom fee Attack.Ransom to unlock the files . After consulting with the FBI 's cyber-crime unit , the department decided to wipe their data server and reinstall everything . Data could not be recovered from backups , as the backup procedure kicked in shortly after the ransomware took root , and backed up copies of the encrypted files . According to the department 's press release , the Cockrell Hill police IT staff said they were infected with the OSIRIS ransomware . It 's quite possible that the department 's server was infected with the Locky ransomware , which a few days prior had come out with a new version that appended the `` .osiris '' extension at the end of encrypted files . The press release says the infection took place after an officer opened a spam message from a cloned ( spoofed ) email address imitating Attack.Phishing a department issued email address . The infection did not spread to other computers because the server was taken offline and disconnected from the local network as soon as staff discovered the ransom demand Attack.Ransom . The department also said there was no evidence of data exfiltration Attack.Databreach to a remote server .