None of the victims of the shooting at Orlando's Pulse nightclub were struck by bullets fired by law enforcement, according to the Osceola-Orange State Attorney's office.

The findings, presented as part of a "shoot review" Wednesday, were based on an investigation by the Florida Department of Law Enforcement and evidence collected by the FBI, which found that 14 law enforcement officers who fired more than 180 shots over a period of four hours were all justified in their actions.

More than 400 rounds were fired during the massacre, the review found -- including by gunman Omar Mateen, who fired 189 rounds with an assault rifle and 22 rounds with a 9mm handgun after he entered the club around 2 a.m. on June 2, 2016. In addition to the 49 people killed in the attack, more than 50 others were injured.

Osceola-Orange Assistant State Attorney Deborah Barra presents the findings of the review. Joe Burbank/Orlando Sentinel via AP

"Each time the law enforcement officer pulled the trigger it was reasonable and justifiable," said Assistant State Attorney Deborah Barra.

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The investigation found that the shooter's assault rifle jammed, and that as he barricaded himself in a bathroom for about three hours he called 911 five times saying he had explosives in the parking lot. He also Googled how to unjam his weapon and spell the word "allegiance" while he hid in the bathroom.

Barra said the gunman was unable to unjam the assault rifle, which she believed "saved lives."

The office reviewed a compilation of evidence including 350 witness statements, police radio traffic, helicopter footage, video from inside the club and 911 calls in an attempt to determine how many officers fired their weapons, why, and where the bullets went, Barra said.

The review found that responding officers engaged the gunman five times before and after the three hours he barricaded himself in the bathroom.

Just before he barricaded himself, officers heard the shooter open fire from inside a bathroom, and they focused on the bathroom door expecting him to re-emerge, Barra said. At that point a survivor peeked out of the bathroom door, and two officers opened fire when he didn't show his hands, Barra said. One officer fired once and struck a mirror, and the second officer fired three times. None of the bullets struck the man, who later complied and was escorted safely out of the club, Barra said.

The shooter would later re-emerge in a hole officers had punched in the concrete around 5:13 a.m. when officers deployed flash bombs, and he opened fire again with a handgun, Barra said. One shot hit an officer in the helmet and another struck a survivor in the calf, Barra said. Thirteen officers -- 10 with the Orlando Police Department and three with the Orange County Sheriff's Office -- returned fire.

The officers struck the gunman seven times, and he fell backward, Barra said. Officers fired at him once more when he was already down because he was near an apparent explosive device, Barra said.

The gunman was pronounced dead at the scene.

"While there is no way to take away the pain and the devastation that has been imparted upon our community, it is my hope that sharing the results of this investigation will help survivors and the loved ones find closure and answer any questions," Ayala said. "They do deserve to have answers."

The gunman's wife, Noor Salman, was acquitted last year of helping him plan the shooting and lying to the FBI.

Orange County Sheriff John Mina, who was Orlando's police chief at the time of the massacre, said officers were relieved by the prosecutor's findings, The Associated Press reported.

"I'm relieved for the officers and deputies, the brave men and women who went inside there and risked their own lives," Mina said. "They now have final closure and relief that they weren't responsible for the death of any victim."