UPDATE 2014: New stabilized version. UPDATE 2012: With the release of the new TV archive at archive.org, the clip has been found on CBS WSBK Boston on 9/11 at 1:35 pm. Thanks to IranContraScumDid911 for posting on YT. See the full CBS/WSBK broadcast without interruption here at 911conspiracy.tv (2nd screen down).
Old YouTube 1 and 2 (links saved in case they are removed from PRIVATE status). The shot aired on the CBS Early Show at unknown time/date (old YT link 1). As the alternate version plays from what appears to be a VCR dub, an eyewitness on the Early Show describes the explosions he heard while escaping (old link 2).
It’s anonymous footage — a handheld camera zooms in, shakes a bit. (See stabilized at link 1 above.) The NE corner flash near floor 91 is obvious. See also 911datasets.org FOIA release 25 for high quality mpeg-2, folder 42A0122 – G25D33.
NIST 14 – CBS-Net Dub5 19
YouTube 1 & 2
