The roommates of Dzohkhar Tsarnaev will be charged with lying to investigators after they allegedly removed items from the bombing suspect's dormitory room and then denied doing so, sources told NBC News.
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The man, in his thirties, was found with stab injuries on the upper deck of a bus in Handsworth, Birmingham, on Monday night.
Thousands of passengers now face delays, with Southeastern trains warning "all services" would be affected.
Paramedics attended a scene in Willesden, north-west London, on Monday afternoon where they found the teenager with stab wounds.