Tsarnaev Social Posts Should Have Been Flagged: Expert

A week after the Boston Marathon bombings, questions emerged about why authorities didn't take more interest in the suspects based on their social media posts and their alleged visit to a terror-related website.

"We're lousy at intelligence," MSNBC military analyst Col. Jack Jacobs said in a CNBC interview on Monday. "In an age of social networks, when these guys posted their feelings on their sites ... nobody picked up on [it]."

Tamerlan Tsarnaev, 26, was killed in a shootout police last week, and his younger brother, Dzhokhar, 19, was wounded before being captured Friday night. The brothers, of Chechen descent, immigrated to the United States a decade ago.

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Investigators told The New York Times they believed the Tsarnaev brothers looked up the design for their pressure cooker bombs on a website of an al Qaeda-affiliate in Yemen. A YouTube account under Tamerlan's name featured two videos about terrorism. An account with Dzhokhar's name on VK, a Russian-language social media site, posted links to videos of fighters in the Syrian civil war and pages calling for independence from Russia for largely Muslim Chechnya.

Jacobs told "Squawk Box" that the U.S. intelligence machine has the technology to track questionable online activities but lack the motivation for social and political reasons.

He described the slippery slope of this type of government monitoring, "It's a public relations and a political problem. On (the) one hand, people don't care if every commercial operation in the world knows everything about them. Crossing the line is the government knowing anything about them."

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The FBI interviewed Tamerlan Tsarnaev in 2011 at the request of the Russians who questioned whether he was possibly linked to extremist groups. The older Tsarnaev then went to Russia for six months before returning to the United States—a trip that's emerged as a focus for investigators.

While Jacobs questioned whether authorities dropped the ball, he said the answer is not more congressional oversight. "The trouble isn't that we need more layers of supervision. We need the people currently charged with the responsibility to supervise our intelligence activities to do their jobs. And they haven't been doing it. And if you're going to extend the bureaucracy, you're just going to make it more difficult to do our jobs."

By CNBC's Matthew J. Belvedere; Follow him on Twitter @Matt_SquawkCNBC. Reuters also contributed this report.