Columbine school shooting victims remembered at 25th anniversary vigil CBS NewsOver 1000 Columbine community members volunteer for day of service 25 years after school shooting CBS NewsNearly 500 People Have Been Killed in School Shootings Since Columbine NewsweekColumbine victim’s sneakers forge a path for his father 25 years later FOX 31 DenverBiden marks 25th anniversary of Columbine shooting The Hill