But until we get a warrant (which did not occur until Sunday evening) how was Comey supposed to know whether there was actually classified e-mails vs a guess or a speculation that there could be classified e-mails.
This is why some democrats and some republicans are very angry at Comey right now. Some democrats and republicans are angry due to political stuff (I honestly do not care about this), other are against what Comey did for it broke Justice Department rules on how to stay out of political fights, and are more about Justice Department independence.
Now for me personally. I am not a democrat, I am an independent who voted in the Republican Primary, but (early) voted in the General for Hillary. Personally I am ambivalent to what Comey did for while in my mind he made the wrong decision, and if he was going to informed Congress he could have done it better than the way he did it in the letter...I am ambivalent for there was no Win/Win in this situation, every choice Comey could have made was a Lose in someway and the Justice Department and Comey would be accused of influencing the election in some way either prior to the election, or after the election occurs when someone was going to leak this and then a vast conspiracy would occur saying Comey was in the tank for Clinton even if he was not.
Personally I am not happy about what happened, but I am often not happy about what occurs in my government (regardless of who is currently running congress or the executive branch). Effectively the milk is on the floor it is all about cleaning it up and doing it better next time.
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Just to recap this is the letter Comey sent
"In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation. I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation," he added.
"Although the FBI cannot yet assess whether or not this material may be significant, and I cannot predict how long it will take us to complete this additional work, I believe it is important to update your Committees about our efforts in light of my previous testimony," Comey concluded in the letter addressed to several lawmakers who chaired committees.
See here for the scanned letter
http://www.nytimes.com/interactive/2016/10/28/us/politics/fbi-letter.html?_r=0