Asked why he didn't leave Littleton after the massacre to escape the reoccurring memories, Friesen said he would have had flashbacks no matter where he lived.
"It was hard at first, but it's really important and was important for me to heal," said Friesen, who avoids news reports about Columbine to this day.
Dave Cullen, author of the best-selling book "Columbine," said many families touched by the Columbine tragedy and those since have stayed in the tight-knit community, shaken together when news of another shooting or bomb scare rocks the area.
"Not everyone realizes that there have been a slew of different bomb scares and threats called in to Columbine High School and other area schools since 1999," said Cullen, who never left Littleton after moving there to report on the massacre when it first happened. "Pranksters play on the fact that they know the administrators have to take it ultra-seriously and they use it against them.
"I've talked to quite a few parents who said when they hear about lockdowns, that they go right back to where they were on April 20, the panic is back," he said.
For Kelley, drawing from the success of rigorous training of parents, teachers and law enforcement officials helps her get through days when she can't believe tragedy has struck again.
"From the ashes of Columbine, so much has been learned, so much has changed," she said. "We saw a response yesterday that proved that and as heavy as your heart is that this happened again, we are so grateful it wasn't worse.
"But there are places in this country that have never experienced one incident like this, and we've had three," she said. "It's difficult."