CHATTANOOGA (AP) — A Tennessee sheriff’s office has lost thousands of videos from dashboard cameras due to a technical malfunction.

A letter delivered to the Hamilton County District Attorney’s Office last week said dash camera footage for all 130 patrol deputies recorded between Oct. 25, 2018, and Jan. 23 of this year was lost after a software failure on Jan. 13, news outlets reported.

Sheriff Jim Hammond said video footage for “any of the hot-button cases that have been going on for the last four months” had already been downloaded, but footage in other cases can’t be recovered.

Hamilton County District Attorney Neal Pinkston said his office will review all cases during the time frame in question.

“Any time there is a loss of evidence, current and future prosecutions can be hindered,” he said. “It will take a case-by-case analysis to determine if a prosecution can go forward. If the only case evidence is lost, then prosecution must cease.”

Hammond said he would use the incident to make a case to the county commission for a more reliable system, which would cost about $1 million.

“It is an expensive purchase, but I’ve always consistently been supportive of anything that ensures the safety of our officers as well as the community,” Hamilton County Mayor Jim Coppinger said. “It’s a big, heavy price tag, and we’ll have to dig deep to find the funds to do that — but sometimes you have to make sacrifices somewhere else to be able to find the funds for something big like this.”