Azamat Tazhayakov was found guilty Monday of obstruction of justice and conspiracy. Prosecutors say he agreed with a friend who removed Tsarnaev's backpack from his dorm room several days after the 2013 bombing. The backpack contained altered fireworks.
Tazhayakov's lawyers argued that the other friend removed the items from the dorm room at the University of Massachusetts-Dartmouth and then threw them away.
Prosecutors told the jury that both men shared in the decision to get rid of the items to protect Tsarnaev. The friend, Dias Kadyrbayev, faces a separate trial in September.