The Romanian hacker Marcel Lazar Lehel, known as "Guccifer," revealed Hillary Clinton's private email use by breaching the account of a Clinton adviser in 2013. (Reuters)

The Hillary Clinton email scandal is often traced back to a front-page New York Times report in March 2015 — and for good reason. The article prompted the FBI investigation that concluded Tuesday with a recommendation not to bring criminal charges against the presumptive Democratic presidential nominee.

But Clinton's use of a private email address during her tenure as secretary of state was actually reported two years earlier. It was just buried inside other stories that seemed like bigger deals at the time.

Flash back to February 2013, when a hacker known as "Guccifer" gained access to the email account of Dorothy Bush, sister of former president George W. Bush. Guccifer went through Dorothy Bush's messages and found family photos and contact information, as well as private correspondence about the health of former president George H.W. Bush. He posted this stuff online. The Secret Service opened an investigation.

A month later, Guccifer hacked former secretary of state Colin Powell, publishing emails and defacing Powell's Facebook page with anti-Bush screeds.

Guccifer — later identified as a Romanian named Marcel Lazar Lehel — was a big story. Lehel was extradited to the United States this year and pleaded guilty in May to aggravated identity theft and unauthorized access to a protected computer.

Before getting caught, however, his next target in March 2013 was Sidney Blumenthal, a senior adviser to former president Bill Clinton. The Smoking Gun, which communicated with Guccifer at the time and reported extensively on his hacks, noted that he seemed particularly interested in Blumenthal's emails to Hillary Clinton. Blumenthal had advised Hillary Clinton during her 2008 presidential campaign.

The emails indicated that Blumenthal continued to share advice when Clinton became secretary of state. And, oh, by the way, the sixth paragraph of the Smoking Gun's follow-up report on the hack contained this little tidbit: "Blumenthal's memos and emails to Clinton were sent to her at a non-governmental email address through the Web domain 'clintonemail.com.' "

Huh. Wonder what that's all about.

Gawker picked up the story a couple days later, but in its coverage, Clinton's use of a private email address took a back seat to the news that she had continued to lean on Blumenthal while at the State Department.

What seems to have escaped notice is that Blumenthal, a fierce Clinton partisan in the 1990s, was the orchestrator of a subterranean smear campaign against [Barack] Obama during the Democratic primary and was specifically spiked by the White House as a potential staffer for Clinton when she became secretary of state. And he was sending notes to Clinton at a private, non-governmental email address. Did Obama know Clinton was consulting with the guy who tried to kneecap him?

The juicy revelation from the Blumenthal hack seemed to be that Clinton kept taking his advice, even after Obama told her not to. The private email appeared to be her way of concealing the relationship. As Gawker put it, "there seems to be little reason to use a different account other than an attempt to shield her communications with Blumenthal from the prying eyes of [Freedom of Information Act] requesters."

We know now that Clinton's private email use was much bigger than that. The key revelation from the Times report in March last year was that Clinton "exclusively used a personal email account to conduct government business as secretary of state" (emphasis added). Once it became clear that Clinton's method of communicating with Blumenthal was no fluke, it became huge news. Three years ago, however, it appeared to pale in comparison to Guccifer's hacking spree and Clinton's consultation of an adviser who had been blacklisted by the White House.

This is how Clinton's private email habit came to light — and also how it went largely ignored for another couple years.