Texas schoolchildren begged for help with officers waiting outside. Be very mad about that.

Why and how did a communication breakdown of this deadly proportion happen?

Outside, police officers in a small Texas community stood guard believing that things were safe inside the school. They believed they had a barricade situation and were no longer responding to an active shooter. 

Inside, meanwhile, children were calling 911 begging for help. They were still being killed. The shooting was still going on. It wasn't over. 

So why and how did a communication breakdown of this deadly proportion happen? How could 19 children and two teachers get gunned down while officers were right outside, waiting? 

The answer to that has been evolving, wrapped in the same miscommunication that days later has left us angry and deflated following America’s latest school shooting.

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One of the big lessons we learned from the Columbine High School shooting 23 years ago is that law enforcement cannot afford to wait for backup in situations like this. They must confront an active shooter as quickly as possible. 

Columbine students and staff were on their own for 47 minutes after shots rang out in their school on April 20, 1999, as police prepared their SWAT response. Two shooters killed 12 students and a teacher. 

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So how could we not be infuriated by the way police mishandled this latest massacre? 

Robb Elementary School students and staff were largely on their own for about an hour on Tuesday, as police worked to secure the scene and prepare their response. One shooter killed 21 people before cops finally took him down. 

A harrowing timeline, many questions 

The truth is we still don't have all the answers, and the more we get from law enforcement, the more questions we have. 

Steven McCraw, director of the Texas Department of Public Safety, explained Friday that the commander at the scene had decided at some point that the incident was no longer an "active shooter" situation. Instead, it had supposedly become a "barricaded suspect" situation. This is why the police said they kept their distance. 

McCraw admitted Friday that the commander screwed up. "It was the wrong decision. Period. There's no excuse for that," he said.

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The shooter entered the school at 11:33 a.m., but officers didn't kill him until about 12:50 p.m. 

We now know the sluggish police response put terrified children through an hour of hell. For some, it was their final hour. 

McCraw summarized 911 calls that came from inside the school: 

► 12:03 p.m. – "She identified herself and whispered she's in Room 112." 

► 12:10 p.m. – She called back and advised there were multiple dead in Room 112.

► 12:13 p.m. – She called again.

► 12:16 p.m. – "She called back and said there was eight to nine students alive." 

► 12:19 p.m. – Another person, in Room 111, called. "She hung up when another student told her to hang up."

► 12:21 p.m. – "You can hear over the 911 call that three shots were fired."

► 12:36 p.m. – The student called back and was told to stay on the line and be very quiet. "She told 911 that, 'He shot the door.'"

► 12:47 p.m. – "Please, send the police now." 

► 12:46 p.m. – She said she could hear the police next door.

► 12:50 p.m. – More shots can be heard over the 911 call.

► 12:51 p.m. – The call becomes very loud and sounds like officers are moving children out of the room. 

Imagine a child begging for help that is somehow both right outside and late to arrive. 

Confusion, chaos and now fury 

Right after the shooting, what the public got was barely a trickle of information, which created more confusion. That came to a crescendo on Friday with one big news conference.

I'm betting officials believed Friday's update would clear things up.

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It did, but doubtful it's the kind of clarity they were hoping for. Instead, it only crystalized an infuriating realization: that 23 years after Columbine, 10 years after Sandy Hook and with a mind-numbing list of school shootings all along the way, we are still not equipped to keep our children safe at any governmental level.

On Tuesday, the response was woefully inept and likely contributed to the number of lives lost in that small Texas town. 

Louie Villalobos is a member of the USA TODAY Editorial Board. Follow him on Twitter: @louievillalobos

Contributing: Steven Porter, Carli Pierson, Rex Huppke