Legal action might involve (1) an FBI investigation, and, (2) the US DOJ---both in the grip of Obama so political hijinks loom. (3) a congressional committee, with subpoena power.
Here's a fourth option: a six-month investigation: indicated the Clintons diverted tens millions of dollars that they solicited for specific Foundation charitable purposes (that were found to have been diverted to the personal enrichment of themselves and their close associates).
THIS IS CONSIDERED MAIL FRAUD Raising money for a specific cause that was diverted elsewhere is considered mail fraud.
REPORT MAIL FRAUD HERE:
https://postalinspectors.uspis.gov/contactUs/filecomplaint.aspx
If the FBI, DOJ and IRS won't shape up to nab the conniving Clintons, the US Postal Inspector has been known to lock-up many crooks for using similar scams.
I read a couple of weeks ago the Benghazi committee is interested in David Brock, which means Media matters.
More than likely some of the emails that are now missing were between Brock/Media Matters and Hillary orchestrating news stories before the Benghazi attack and directing the spin of the news after the attack.