Nightly News | May 16, 2013
>>> it's been almost a month since another disaster hit texas, in the small town of west, texas, near waco. first there was that raging fire. then the massive explosion that killed 15. 12 of the killed were first responders who were trying to fight the fire. tonight investigators say they still do not know what caused the initial fire. they've ruled out smoking or weather conditions, spontaneous combustion thamp say they'll continue to look for clues in what is still classified as a criminal investigation.