Two Colorado Commanders Recall Columbine Eight Years Later

Both men were intricately involved at the April 20, 1999 deadly high school shooting.

Police officers also went into the classrooms to develop relationships with students. "We tell them it's OK to report something suspicious or someone who is acting strangely," Walcher said.

In addition, regional SWAT teams were formed, and they practice specific techniques developed after the incident. EMTs and paramedics were added to the squads as well.

Pessemier said radio communications have been enhanced that enables agencies to talk to one another should a similar incident arise.

All those involved in the incident -- including the school district -- are familiar with what's expected of them. "We're better prepared because we all have a better relationship," Walcher said.

"What happened in VT is just absolutely tragic," he said. "So very said."