The City of Dallas has released a 131-page report on thousands of criminal cases that may have been affected by the significant data loss that occurred earlier this year. The city lost about 21 terabytes of data with over eight million files in the data losses on March 30 and 31.

The files lost include archived images, video, audio, and case notes from the Dallas Police Department. The Dallas PD previously said that the FBI was investigating to determine if the employee who lost the files did so intentionally. The City Council will determine whether to hire an independent investigation to look into the case later this month.

Officials say that there is a possibility that about 17,500 cases would be affected by the loss, including the 1,000 cases prioritized by the Dallas County District Attorney’s Office.

An excerpt from the report reads, “City personnel failed to faithfully follow the data migration procedures […] provided by the software vendor and found there is a lack of understanding among the IT staff and leadership as to the importance of data management controls, policies, standards, and procedures.”

“The findings in this report are troubling and distressing,” Dallas Mayor Eric Johnson said in a statement. “The report details ‘inadequate’ and ‘insufficient systems and controls, reveals significant management deficiencies, and demonstrates, again, the failure to take these matters seriously enough. All of it raises further questions. We need action and accountability. I want the Dallas City Council’s Ad Hoc Committee on General Investigating and Ethics to receive a full briefing on the report this month.”

Andrew Wildrix, Chief Information Officer at the Plano firm Intrusion, reviewed the report of the massive data loss and called it a “disaster.” “Anytime data is lost, I consider it a disaster, especially on that level of magnitude,” he said. According to Wildrix, the data loss was preventable.

Assistant Dallas County Public Defender Brad Lollar also reviewed the city’s report and was surprised by the number of cases affected. Lollar, who is representing eleven defendants charged with capital murder, says that he does not know if any evidence from those cases was lost.

Lollar said that he and other defense attorneys are waiting for information on the cases that are impacted.