(CNN) Columbine High School in Colorado -- where two students killed 12 classmates and one teacher before dying by suicide 20 years ago -- will not be torn down and rebuilt, according to a statement issued Wednesday by Superintendent Jason Glass of Jeffco Public Schools.

Instead the Littleton, Colorado, high school, where about 1,700 students in grades 9 through 12 are currently enrolled, will implement "changes to enhance the security and privacy of the site, including the creation of an improved and defined perimeter around the building," he said.

The discussion about replacing the original school was driven "by the number of 'unauthorized individuals' (some 2,401 as reported in the Colorado Sun) who came onto Columbine's grounds this past school year," stated Glass.

In a previous letter, Glass had noted that, annually, "hundreds of individuals seeking to enter the school and reconnect with the 1999 murders" come to the attention of local law enforcement. "Most of them are there to satisfy curiosity or a macabre, but harmless, interest in the school. For a small group of others, there is a potential intent to do harm," he said.

In April, for example, the FBI reported that a high school student who was "infatuated" with the Columbine shooting had traveled from Florida to Colorado and made credible threats. Later, the student -- 18-year-old Sol Pais -- was found dead from an apparent self-inflicted gunshot wound, authorities said.

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