And the controversy over last week’s 60 Minutes report on President Bush’s military service in the Texas Air National Guard continues. For the first time CBS News and Dan Rather admitted the * possibility that their report was based on forged documents. But Rather continued to stand by his reporting. The documents in question were allegedly from the personal files of the late Lt. Col. Jerry Killian, who served as Bush’s squadron leader in the Texas Air National Guard. Yesterday Rather interviewed Killian’s secretary * Marian Carr Knox. She told CBS that she believes the * documents are fake* but that they reflected the sentiments of Kilian. In other developments, the New York Times is reporting that an unnamed employee at CBS is saying the source of the controversial documents was * Lt. Col. Bill Burkett*. Burkett is the Texas Air National Guardsman who has previously said he witnessed Bush’s military records being purged in the late 1990s as the then governor was preparing to run for the White House.