Pulse nightclub shooter used Google during three-hour standoff with police

The man who murdered 49 people at a Florida nightclub used Google while taking shelter from police in desperate hopes of fixing his jammed assault rifle, authorities said Wednesday.

Nearly three years after Omar Mateen's deadly rampage at the Pulse, a gay nightclub in Orlando, Orange-Osceola State Attorney Aramis Ayala cleared all 13 police officers and sheriff's deputies who opened fire that night.

Every officer-involved shooting in Florida must be reviewed by local prosecutors, and Ayala found that all rounds fired by responding police and sheriff's deputies were justified.

And during a 40-minute-long press conference, Ayala and Assistant State Attorney Deborah Barra revealed several new details of what was once America's worst mass killing.

Mateen was armed with an assault rifle and pistol when he walked into Pulse on June 12, 2016. That rifle jammed during the assault, before Mateen took shelter in the restroom for three hours.

While hunkered down, Mateen called 911 five times and used his smartphone for internet research.

"He was also on his phone and he was Googling how to spell the word 'allegiance' and he also tried to research how to unjam his firearm," Barra said. "Again, we know that he was not successful in figuring that out."

When police finally busted down a wall and used a flash-bang grenade to disorient Mateen, 10 officers and three deputies descended on the killer, Barra said.

Officers fired 172 shots, striking Mateen seven times, she added.

Mateen had earlier told police he had explosives. So when law enforcement approached Mateen's lifeless body, they spotted what looked like wires on him, and they feared he still might be able to trigger a bomb.

That's when one officer fired one more shot into Mateen's prone body, prosecutors revealed.

But it turned out, the wires near Mateen were from an "exit" sign that had fallen on him during the final shootout, authorities said.

"When the officer walks up and, knowing that he had previously talked about bombs being present and he saw wires and whatnot, it only takes that for something terrible to happen," Barra said, pressing her thumb to her index finger simulating a detonation.

"And so the officer made sure that did not happen."

At the time, Mateen's killing spree was the worst mass shooting in U.S. history.

It was eclipsed on Oct. 1, 2017, when Stephen Paddock murdered 58 people at a country music festival in Las Vegas from his nest on the 32nd floor of the Mandalay Bay Resort.