Last month, when Wikileaks published 20,000 emails stolen from the Democratic National Committee, cyber-security experts quickly said that the hack bore a Russian fingerprint.

Russia denies that it is trying to meddle in the U.S. presidential election. But Mark Galeotti, who follows cyber-crime for the Institute for International Relations in Prague, says worldwide research points in the Russians' direction.

"When cases like this crop up, you have literally thousands of people who will seek to follow the breadcrumbs," he says. "And essentially, this has all proven consistent with the idea that this is a Russian hack."

Investigative journalist Andrei Soldatov says the hack wasn't necessarily the work of Russian intelligence services.

"It's much more complicated than that," says Soldatov, co-author of The Red Web: The Struggle Between Russia's Digital Dictators and the New Online Revolutionaries. "We have non-government actors, and they're really adventurous, really fast and they're really, really good."

He says mercenary hackers give the government a way to deny involvement.

Once the material had been stolen, though, Galeotti thinks the Kremlin took over.

"The actual leak — the point where they did something with the information they gathered — now there's no question that that would be regarded as a strategic move, and would need to have had Kremlin sanction," he says.

Russia's foreign minister, Sergei Lavrov, repeated this week that Russia doesn't interfere in the affairs of other countries. Recently he said, "We have witnessed a volley of Russophobic hysteria."

He called the accusations "ploys to support one candidate and smear another."

DNC staffers charged that the publication of the emails was a Russian ploy to support the candidacy of Donald Trump. But "I think it's not about Trump," says Soldatov. "It's all about Hillary Clinton."

What might Russia hope to gain from influencing the American vote?

Soldatov says President Vladimir Putin believes Clinton is a Russia-hater who was behind anti-government demonstrations that took place in Russia in 2011 and 2012.

And Soldatov says this U.S. election is important for Moscow because America's next leader could determine whether economic sanctions against Russia will be lifted. "And everybody in the Kremlin believes that if Hillary Clinton in the White House, it will be absolutely impossible to get the sanctions against Russia lifted. So in a way, it's a question of national security for Russia."

Galeotti thinks the key purpose with the DNC leaks is to divide Clinton's political base by showing that top party officials worked to freeze out her primary opponent, Bernie Sanders.

The Kremlin's idea, he says, is to create the impression that politics in the U.S. is manipulated just as much as in Russia.

"What they're trying to do is build a kind a propaganda campaign not so much intended to win it allies and friends, but to always give the impression that everyone is just as bad," he says.

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