VIRGINIA BEACH, Va. (WAVY) — While police examine officer body camera footage from the Virginia Beach mass shooting, they won’t have video from the four officers who engaged the shooting suspect in a gun battle.

In an update released Thursday, the city said none of the four officers who confronted the shooting suspect on May 31 were wearing cameras. Other officers who helped secure the building had cameras on at the time, and police are looking through that footage. The city didn’t give an explanation why those who engaged the suspect didn’t have cameras.

The city says more than 300 interviews have taken place, and 20 search warrants have been conducted for data from cell phones, computers personnel files, and medical and financial records, adding up to 69 gigabytes to be organized and analyzed.

At least four homicide detectives and one lieutenant from the Virginia Beach Police Department are assigned full-time to the department’s investigation. A captain and VBPD Detective Bureau sergeant are also separately investigating the officer-involved shooting aspect of the incident.

Meanwhile the FBI is conducting its own investigation, which could take as long as a year to complete, but a preliminary report should be released much earlier. The city says investigations into similar mass shootings take about 6 to 10 months to complete.

Several families of the victims have also called for an independent investigation, separate from the police department and FBI’s. They claim the city hasn’t been transparent about the suspect’s standing within the Public Utilities Department, and they want to know if warning signs were missed or ignored.

Also in the update, the city says an eight-foot-tall security fence and privacy slats costing around $64,000 are being constructed around Building 2, with a completion date around mid-July.