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The Florida state attorney's office has ended a six-month investigation into the Pulse nightclub shooting, concluding no civilians were shot by law enforcement.

The question of friendly fire has plagued law enforcement since the June 2016 shooting left 49 dead during Latin Night at the predominantly gay nightclub in Orlando. The state attorney used the FBI's ballistics report, as well as witness accounts, video evidence and 911 calls.

Law enforcement opened fire five separate times during the standoff, which lasted more than three hours. In total, 14 officers fired more than 180 shots — but hit no civilians, the report found.

All 14 officers have received clearance letters from the state attorney that the shooting was reasonable and justified. Eleven of the officers were with the Orlando Police Department, and three were members of the Orange County Sheriff's Office, NPR reports.

Orange County Sheriff John Mina — formerly the Orlando Police Department's chief — said an announcement like this could bring back emotional trauma for first responders.

"Reviews of these incidents sometimes bring back those feelings," he said, offering services including an employee assistance program and the organization UCF Restores.

UCF Restores is a government-funded clinic for veterans and first responders with post-traumatic stress disorder. An investigation last year by WMFE and ProPublica found multiple first responders to the Pulse nightclub shooting struggling with PTSD years after the event.