ARVADA, Colo. —  Arvada Police Deputy Chief A.J. DeAndrea has responded to three school shootings during his watch.

For him, the violence at Columbine was only the beginning.

Seven years later he was on the SWAT team that confronted the gunman who killed Emily Keyes, 16, at Platte Canyon High School near Bailey.  He was just feet away from her when she died.

“I’ve got a picture of Emily right here on my wall, and it reminds me every day about what this job is, the ramifications of this job, and what my obligation is back to this community,” DeAndrea told FOX31.

“Everyday when I walk in here I see that. I still wear this bracelet,” he said, pointing to a bracelet that says “I love u guys.”

That was the message Keyes texted to her parents on September 27, 2006, before she was killed.

Almost a year later, DeAndrea responded to another school shooting.  The Youth With a Mission missionary school shooting in Arvada on December 9, 2007.  He was the fourth officer inside the building, where they found four gunshot victims, including Philip Crouse and Tiffany Johnson.

He helped carry them both out of the building before they both died at the hospital.

But police had every victim out of the Arvada missionary school building within 10 minutes of the first 911 call.  It was proof of the skills they learned after Columbine, like quicker responses and no longer waiting for SWAT officers before entering the building.  Now, they teach patrolmen how to get inside a school right away if there’s a gunman.

And from the Platte Canyon shooting came something called the Standard Response Protocol.  It’s training that’s now in place in 22,000 schools across the US and Canada, aimed at getting police and schools on the same page and using the same language, along with creating lock-down and lock-out procedures that keep people alive.

“I truly believe that lessons learned from Columbine helped save lives that day,” DeAndrea said.

And even his day-to-day conversations since Columbine may have helped save at least one precious life: his own daughter’s.  As fate would have it, she was inside the Borderline Bar and Grill in Southern California last November when a shooter killed 12 people.

“And I get a text from my daughter that says ‘I love you guys,’ just like Emily Keyes,” he said.

Thankfully, because of so many conversations with her father, she knew exactly what to do.

“She looks around the kitchen, and she actually sees a lady climbing into the attic. There`s a ladder on the wall, she sees this other lady doing it, and so she does too, and more people followed her,” DeAndrea said.  After an hour and a half, SWAT team members rescued her and the others barricaded inside.  Just as DeAndrea did at the Columbine shooting 20 years ago.  The first of his three school shootings.

And he thinks there will be a fourth.

“My biggest question is, have I prepared the men and women here at the Arvada Police Department?  Have I prepared the TAC teams that I’ve trained across the country?  Have I prepared the law enforcement officers that I’ve trained all over the world to do it right, and to do it better?  Because the day is coming,” DeAndrea said.