I saw a lot of blinking but no tearing. Comey looked at all of Clinton's behavior and concluded their was no intent to cover-up or withhold evidence.

Obstruction of justice and lying to Federal law enforcement officials, are prosecutable offenses. They are often prosecuted when there is no evidence to support other charges. See U.S. V Martha Stewart.

http://money.cnn.com/2004/03/05/news/companie...a_verdict/

Considering the length of the investigation it's highly improbable that if the Feds could have prosecuted for obstruction, that they wouldn't have.