Interview: Boston Marathon Trials Set To Begin
Tazhayakov is being charged with obstruction after he and another friend, Dias Kadyrbayev, took a backpack containing fireworks and a laptop from Tsarnaevs dorm room and tossed it out.
The two saw Tsarnaev's picture on TV and responded to a text from their friend, asking if they could go to his dorm room and remove what was there. Both men pleaded not guilty.
The trial will determine if Tazhayakov was intentionally trying to hinder the investigation. It is expected to last two to three weeks.
ABC News correspondent Scott Goldberg joined us for more:
Follow us on Twitter: