Joe Biden blasts Tsarnaev brothers as ‘knock-off jihadis’ (VIDEO)

Never one to mince words, Joe Biden blasted the suspected Boston bombers as "knock-off jihadis" in a memorial service for a slain MIT police officer.

“Why, whether it’s al Qaeda central out of the FATAs or two twisted, perverted, cowardly, knock-off jihadis here in Boston. Why do they do what they do?” he asked rhetorically.

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Biden then knocked the brothers again during an extended appreciation for police officers.

“You are their worst nightmare,” he said. “All the things, these perverted jihadis, self made or organized, all the things they fear.”

“The only way they can gain ground is to instill fear that causes us to jettison our values, way of life, for us to change," Biden added. “The moment we change, the moment we look inward, the moment we get into a crouch in a defensive, that’s the moment when they win.”

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The vice president was one of several lawmakers who spoke at today's memorial for Sean Collier, a 27-year-old MIT campus officer who authorities say was shot and killed by Tamarlan and Dzhokhar Tsarnaev last week.

More than 10,000 people gathered at Briggs Field on the MIT campus for the memorial, many wearing "Collier Strong" badges on their shirts.