Tsarnaev suffered at least two bullet wounds -- including one to his neck -- before he was arrested in Watertown, CBS News security analyst John Miller said Saturday night.
The bullet wound to the neck, which has an exit wound in the back of the 19-year-old's neck, "is very possibly a suicide attempt," said Miller, a former assistant director at the Federal Bureau of Investigation.
Miller also said the neck wound is the primary reason why Tsarnaev is unable to speak with investigators, who are hoping to interrogate the suspect to find out, among other factors, whether he and his older brother acted alone in the bombing attack on the Boston Marathon.
Three people were killed and more than 180 injured in the two bomb blasts near the Boston Marathon finish line.
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