looking for people. this building stood for decades. what could have caused this to happen? very simply. >> well, there could be a lot of factors. it will be some time before we sort it out. we typically, when doing investigations like this, we're looking at construction issues, design issues, materials and alterations questions. maintenance. the primary question that the investigators are going to be focusing on is why did this building stand for 24 years and then collapse suddenly this morning? what changed? what changed in the structure and the loading and other factors inpinged on it.