The plot thickens.  Not only Hillary Clinton, but her top aides used secret private e-mail accounts for official business.  This makes a mockery of the public records law and has already led to requests under the Freedom of Information Act being stonewalled, as the State Department has (truthfully) responded that it has no records.  Michael S. Schmidt and Amy Chozick write in the New York Times:

In 2013, Nitasha Tiku, then a reporter for Gawker, filed a Freedom of Information Act request, seeking all correspondence on Mrs. Clinton’s private email account between her and Sidney Blumenthal, a close adviser and onetime staff member in the Clinton White House. Some of those emails had already spilled into public view and been reported in the news media. But the State Department told Gawker that it could find no records responsive to the request, Gawker reported. (snip)

The Associated Press said its FOIA requests for records related to Mrs. Clinton’s tenure at the State Department, the oldest of which was submitted in March 2010, were not answered. In addition to requesting Mrs. Clinton’s schedules, The A.P. asked for correspondence related to Huma Abedin’s special arrangement to serve as a top adviser to Mrs. Clinton and consult for private clients. “We have not received any documents yet, despite the promised deadlines, and we are evaluating the situation,” said Erin Madigan White, spokeswoman for The A.P.

J. K. Trotter of Gawker explains:

…according to a knowledgeable source, at least two other top Clinton aides also used private email accounts to conduct government business—placing their official communications outside the scope of federal record-keeping regulations.

“Her top staffers used those Clinton email addresses” at the agency, said the source, who has worked with Clinton in the past. The source named two staffers in particular, Philippe Reines and Huma Abedin, who are said to have used private email addresses in the course of their agency duties. Reines served as deputy assistant secretary of state, and Abedin as Clinton’s deputy chief of staff. Both rank among Clinton’s most loyal confidantes, in and out of the State Department.

We were able to independently verify that Abedin used a ClintonEmail.com address at some point in time. There are several email addresses associated with Abedin’s name in records maintained by Lexis-Nexis; one of them is huma@clintonemail.com. An email sent to that address today went through without bouncing.

The Clinton camp has been defending her use of seret e-mails on the grounds that e-mails to other officials would be captured by the official e-mail archiving, since they were sent to state.gov accounts.  However, the fact that her top aides were not on that system means that her most candid and serious communications were shielded from public disclosure as required by law.