Kevin Ryan is pwning the UL flip flop (Of course we certified the steel, here are the papers - then - no, of course we never certified that steel).
The story will be well known by year two of the next administration.
It's my take that they will wait til Silverstein dies (or fakes his death, how hard is it?), and they will later say "yes, there may have been explosives, we are not sure. Perhaps someone in Larry Silve's company was in on it, but we will never know" or some bullshit like that.
Ironically, you'll have President Rudy (the same guy who shipped away the crime scene in violation of federal law) standing up, talking about how "even if there were others involved, we have won! We have conquered the nations of Syria and iran, after we learned they helped silversteins' people. We're also looking at the WMD that Colombia has..."