'' Planetary '' , another Wildstorm series by Ellis and John Cassaday , launched in 1999 , as did Ellis 's short run on the DC/Vertigo series '' Hellblazer '' . He left that series when DC announced , following the Columbine High School massacre , that it would not publish " Shoot " , a '' Hellblazer '' story about school shootings , although the story had been written and illustrated prior to the Columbine massacre . '' Planetary '' concluded in October 2009 with the release of issue 27
Columbine High School massacre
Columbine High School massacre
Warren Ellis