Daniel Mauser was a 15-year-old sophomore at Columbine High School in Littleton, Colorado, described as gentle and mild-mannered and strong in math and science. Despite shyness he joined the school debate team to challenge his fear of public speaking, and two weeks before his death he had discussed concerns about loopholes in the Brady Bill with his father.

On the morning of April 20, 1999, Daniel was studying in the school library when two senior students, Eric Harris and Dylan Klebold, carried out a planned assault. After shooting elsewhere in the school they entered the library where many students were hiding. Daniel took cover under a table; he was shot once, pushed a chair toward one attacker, and was then shot again, fatally, in the face. He was one of twelve students and one teacher murdered during the massacre. The two perpetrators died by suicide in the library, ending the attack.

Investigators later found the shooters had used firearms obtained with assistance from others; two men, Mark Manes and Philip Duran, were arrested and later sentenced in connection with supplying weapons and introductions. If anyone knew Daniel or was with him that day, please share what you remember.