While most of the attention on Hillary Clinton's emails dealt with a document that included instructions from Clinton to tamper with the headings of a possibly classified subject, another, even more explosive email is big news in Sudan and could potentially lead to criminal charges.

The email in question is from Sid Blumenthal, close Clinton friend and ally, who was in Libya trying to drum up business with the Libyan government for some business associates. To ingratiate himself with Secretary Clinton and get the State Department to intercede with the Libyan government on his behalf, he sent her "intelligence" briefs on what was happening on the ground in Libya and elsewhere in the Middle East.

One of them is explosive. It involves a conspiracy in the Sudanese government to ally themselves with some rebels in order to get their hands on some oil fields. The problems for Blumenthal and Clinton:

1. The email contains what appears to be information gleaned from National Security Agency intercepts. 

2. For some reason, the State Department did not mark the email "classified" or "Secret" as they should have.

3. Even if it wasn't marked "Classified," Clinton should have seen the incredible sensitivity of the information.

New York Observer security reporter John Schindler is a former NSA officer and says he knows what agency intercepts look like:

This message includes a detailed intelligence report from Sid Blumenthal, Hillary’s close friend, confidant, and factotum, who regularly supplied her with information from his private intelligence service. His usual source was Tyler Drumheller, a former CIA senior official and veteran spy-gadfly, who conveniently died just before EmailGate became a serious problem for Hillary’s campaign.

However, the uncredited June 8 memo, which Mr. Blumenthal labeled as “Confidential” – his personal classification system, apparently – but which the State Department has labeled Unclassified, doesn’t appear to be from Drumheller, whose assessments were written just like CIA intelligence reports. This is not.

Remarkably, the report emailed to Hillary by “sbwhoeop,” which was Mr. Blumenthal’s email handle, explains how Sudan’s government devised a clandestine plan, in coordination with two rebel generals, to secure control of oil reserves in the disputed region of Abyei. This is juicy, front-page stuff, straight out of an action movie, about a region of Africa that’s of high interest to the American and many other governments, and the report is astonishingly detailed.

But the most interesting part is that the report describes a conversation “in confidence” that happened on the evening of June 7, just one day before Mr. Blumenthal sent the report to Secretary Clinton. It beggars the imagination to think that Sid’s private intelligence operation, which was just a handful of people, had operators who were well placed in Sudan, with top-level spy access, able to get this secret information, place it in a decently written assessment with proper espionage verbiage, and pass it all back to Washington, DC, inside 24 hours. That would be a feat even for the CIA, which has stations and officers all over Africa.

In fact, the June 8, 2011 Blumenthal report doesn’t read like CIA material at all, in other words human intelligence or HUMINT, but very much like signals intelligence or SIGINT. (For the differences see here). I know what SIGINT reports look like, because I used to write them for the National Security Agency, America’s biggest source of intelligence. SIGINT reports, which I’ve read thousands of, have a very distinct style and flavor to them and Blumenthal’s write-up matches it, right down to the “Source Comments,” which smack very much of NSA reporting and its “house rules.”

The implications here are staggering. If Blumenthal had somehow gotten his hands on NSA intercepts and sent them to Clinton using unsecured and non-classified means, he should get his affairs in order and measure himself for an orange jumpsuit. He is going to jail. The NSA will make sure it's hard time too.

Clinton is hardly off the hook, even though there was no classification on the email. A novice would have read about the Sudanese plot and realized how explosive the information was. A responsible secretary of state would have immediately classified the document and broken off all communication with Blumenthal.

At the very least, this makes Hillary Clinton vulnerable to criminal charges. Negligent handling of classified material is a felony and I don't think a prosecutor would have much trouble proving negligence. 

Another mystery: Why did the State Department release this email in the first place? Someone fell asleep on the job because this is the sort of intelligence that brings down governments. We'll have to see what happens in Sudan over the next few days as the fallout continues.

Schindler concludes:

It’s possible this Blumenthal report did not come from NSA, but perhaps from another, non-American intelligence agency – but whose? If Sid was really able to get top-level intelligence like this for Hillary, using just his shoestring operation, and get it into her hands a day later, with precise information about the high-level conspiracy that was just discussed over in Sudan, the Intelligence Community needs to get him on our payroll stat. He’s a pro at the spy business.

Or perhaps Blumenthal's CIA source, Tyler Drumhell, made up the whole thing. Drumhell publicly accused the Bush administration of fabricating WMD intel in order to justify the invasion of Iraq, so he's not the most credible or balanced of sources. Still, Schindler believes at the very least that some SIGINT agency - NSA or foreign - has a serious leak.

More than the other email where Clinton ordered an aide to tamper with a classified document, this could be the dagger that finally fells Hillary Clinton.