Why did DC GOV not fully investigate the 9-11-2001 attack event better?&why no official test for explosives?

Conspiracy theorists usually have their own agendas including 1) Anti-Bush people who want to blame everything that goes wrong in the world on Bush (There are Anti-Obama people who blame everything on Obama but that doesn't pertain here.) 2) Anti-government people who blame everything on the government whoever is in charge 3) Anti-Americans who blame America first for everything 4) Moslems who don't want to take responsability for it . 5) Anti-Semites who want to blame the Jews for everything and probably other groups I haven't thought of.