The brilliant and recently ended TV series, The Americans," depicted the lives of two Russian KGB "sleeper" agents posing as an American couple during the Cold War. By day, they ran their travel agent service and raised their all-American kids. By night, they assassinated Kremlin critics, stole military secrets, carried on sexual relations with marks with access to intelligence and much more.

KGB "sleeper" agents living for decades in the US as Americans were and probably are a real thing.

Now, we've learned, the Russians have invented the concept of "sleeper" news sources.

An analysis by NPR found that 48 of the fake news sites formerly maintained on Twitter by Putin's paid trolls at Internet Research Agency were local news sites that didn't post or link to fake news at all.

These sites posed as local newspapers, such as @ElPasoTopNews, @MilwaukeeVoice, @CamdenCityNews and @Seattle_Post.

They took advantage of closed newspapers. For example, they had a Chicago Daily News Twitter account, a newspaper that closed in 1978. That account existed for years before being suspended by Twitter, accumulating 16,000 followers.

The most shocking fact is that these accounts posted real news, not fake news.

Their purpose appears to be to use both the "local news" angle and also the trust built up by posting real news to build trust among followers. In the event of some major future news story important to the Kremlin, they would only then post the fake news to throw the truth into doubt.

Smart readers can often spot fake news, and ignore it, especially when an account repeatedly promotes fake news. But building reader trust with real news is more dangerous.

Russia is playing a long game on disinformation designed to destabilize the United States.