"Comey's letter was the culmination of a fast-paced review of the newly discovered email, law enforcement sources said Sunday.
"We went through this as fast as we could," a senior law enforcement official told CNN, with another law enforcement official saying investigators worked "around the clock" to review the large volume of emails.
The FBI found the new emails as part of its separate investigation into a sexting incident by Anthony Weiner, the estranged husband of top Clinton aide Huma Abedin.
The thousands of new emails were mostly personal and duplicates of what had already been seen, law enforcement officials said in explaining how the conclusion was reached so quickly. The laptop which was found was about a decade old with lots of personal content on it not relevant to the investigation, according to one source.
The probe is considered over with regard to Clinton. Though with not all the deleted emails recovered and not all the devices in FBI's possession, it is always possible something else could turn up that would require more review.
There were some classified emails found, but law enforcement officials stressed the issue is not the classified information so much as proving intent. The sources would not specify if the the classified messages were new or duplicates of ones already reviewed, nor would would officials say how many there were and what levels at which they were classified.
"Keep in mind we are focused on intent," the official said. "We know there are classified materials, but that doesn't change the conclusion reached back in July."
Also, the 55,000 email review from her server was of paper copy, as the electronic records were not provided:
http://money.cnn.com/2015/03/11/technology/security/hillary-email-paper/