(NBC NEWS) Boston Police said Wednesday they have arrested three more people in the marathon bombing investigation, but gave no additional details.

Sources told NBC News the three are college roommates or suitemates of accused bomber Dzokhar Tsarnaev and are suspected of removing items from his dorm at the University of Massachusetts-Dartmouth.

There was no indication they had any prior knowledge of the bombing. Sources said the FBI had been investigating them for about 10 days.

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