    tence 4: Harris ..and.. Klebold’, Killed: :12  itudent’s’ and.a teacher before “taking their: own  fives’ on April20., 1999:    nitence 2: Hanis" avd. ‘Klabotd. killed ° 12  itudents ’, . a- teachér’-and. -thettidelvés “atthe  hol. : : :