I've already stated that there is no way to prove Powell's use, as he stated he has none of those emails, as referenced in the link above.
Hey, I'm not the one accusing someone of felonies without proof.
From your link, Powell did state: "I am not sure HRC even knew or understood what was going on in the basement" which I can only believe means that she herself wasn't 100% aware of the technical aspects of her email support, so you'll need to provide proof that she intentionally kept anything hidden on her private email server.
How about the fact that she specifically ordered someone to send classified material "nonsecure" and remove the classified headings?
But in one email exchange between Clinton and staffer Jake Sullivan from June 17, 2011, the then-secretary advised her aide on sending a set of talking points by email when he had trouble sending them through secure means.
Part of the exchange is redacted, so the context of the emails is unknown, but at one point, Sullivan tells Clinton that aides "say they've had issues sending secure fax. They're working on it."
Clinton responds, "If they can't, turn into nonpaper w no identifying heading and send nonsecure.
- CBS News
We don't know that at all. We know that the State Department and the campaign were claiming that to the New York Times a year ago, (your article is from January), but "the truth" about Clinton's emails has changed several times since then.
At this point, I'd state that you'd need to prove that a single classified email with known classified information with the proper relationships in the document to actually make them classified was sent knowingly by Clinton from her private email server. Retro-active classification does not qualify.
Do I have to prove it? Can the FBI prove it instead? Let's ask FBI Director James Comey what he found on the server.
From the group of 30,000 e-mails returned to the State Department, 110 e-mails in 52 e-mail chains have been determined by the owning agency to contain classified information at the time they were sent or received. Eight of those chains contained information that was Top Secret at the time they were sent; 36 chains contained Secret information at the time; and eight contained Confidential information, which is the lowest level of classification. Separate from those, about 2,000 additional e-mails were “up-classified” to make them Confidential; the information in those had not been classified at the time the e-mails were sent...
For example, seven e-mail chains concern matters that were classified at the Top Secret/Special Access Program level when they were sent and received. These chains involved Secretary Clinton both sending e-mails about those matters and receiving e-mails from others about the same matters. There is evidence to support a conclusion that any reasonable person in Secretary Clinton’s position, or in the position of those government employees with whom she was corresponding about these matters, should have known that an unclassified system was no place for that conversation. In addition to this highly sensitive information, we also found information that was properly classified as Secret by the U.S. Intelligence Community at the time it was discussed on e-mail (that is, excluding the later “up-classified” e-mails).
And one last thing.
If it came from an unclassified source, it's not classified, even if the gov wants it to be classified.
So everyone reading this blather knows, this is false. It doesn't even support the point you're trying to make. Think about it logically. If someone found out the nuclear launch codes and emailed them to someone, do the nuclear launch codes automatically become declassified? Or take these emails. The State Department is publishing them with redactions for classification. Why would they still be classified if they came from Hillary's unclassified system?