[dropcap]A[/dropcap] feeling of tension cast over roughly 150 residents at Dripping Springs High when 911 phone call recordings from the 1999 Columbine school shooting were played.

The tapes, which rarely have been heard by the general public, offered a moment of shock for some. All, however, attentively listened to those who reported what was at the time one of the worst mass shootings in American history. 

For Hays County Sheriff’s Office Lt. David Burns, the recordings offered a chance ...