An LA Times article by David Willman discusses an email response by virologist Peter Jahrling, one of the first people to examine the Daschle anthrax, and to remark repeatedly on its properties that indicated deliberate weaponization:
After being informed of the events at the (9/16/2008 House Judiciary Committee) hearing, Jahrling renounced his earlier analysis. “In retrospect,” Jahrling said, “I believe I was mistaken and defer to the experts.”
In “The Demon in the Freezer,” a 2002 book by Richard Preston, Jahrling:
…said that USAMRIID had found that the anthrax powder in the letter mailed to Senator Daschle was “professionally done” and “energetic”. By “energetic” he meant that the particles had a tendency to fly up into the air if they were disturbed.
Please see Comments 3 and 4 for an informed and referenced discussion on this.
Mueller was also interviewed by Preston. He attended Jahrling’s White House briefing, and:
Mueller thanked the Army for bringing the nature of the anthrax to the FBI’s attention. He said that the FBI had received conflicting data on the anthrax. The FBI had been trying to sort this issue through, but Mueller now acknowledged that the Army had been right: the Daschle anthrax was a weapon.
Well, Jahrling may be correct now. Or he may have been correct then. Same goes for Mueller.