Eric Harris's Doom WAD levels (partially lost Doom WAD levels; 1990s)
The Columbine High School shooting occurred on April 20th, 1999, and killed 13 people while injuring many more. The two perpetrators were two seniors, Eric Harris and Dylan Klebold. Before the shootings occurred, Harris, an avid player of the video game Doom, was known to a few to create various Doom WADs (WAD being the default package of files for the game), many of which can be found here. There were numerous WADs he shared with his friends, including THRASHER.WAD, REALDETH.WAD, and more. According to page 7043 of the 11,000 pages Columbine Report, Eric Harris was quoted as saying that he had created "a level in Doom that was Columbine High School," leading some to falsely believe that Harris and Klebold were practicing the shooting in the WAD. According to some, "realdoom.wad" is rumoured to be the WAD in question.  No evidence has surfaced as of yet to confirm this. Even if it was, the WAD in question is currently lost and cannot be downloaded.
A possible lead has been found on June 15th, 2019. In one of Harris' recently discovered wads, he mentions "realdoom.zip," which might be the rumored Columbine level.
- Doom (lost FMV scenes and original work of 3DO port of first-person shooter game; 1994-1995)
- Doom (lost prototype of Sega Saturn port of first-person shooter; 1996-1997)
- Doom (lost reference photographs for first-person shooter game cover art; 1993)
- Doom (partially found production materials of cancelled first-person shooter game film adaptations; 1994-1999)
- Doom and Doom 2 (partially lost original sound files of first-person shooter series audio; 1993-1994)
- Doom 4 (lost build of cancelled sequel based on "Doom" first-person shooter series; 2007-2014)
- Doom Absolution (lost build of cancelled Nintendo 64 sequel to "Doom 64"; 1997)
- Doom "Episode 5" (lost build of cancelled expansion to first-person shooter; 1995)
- http://acolumbinesite.com/reports/cr/p7001-7100.pdf, page 43