His brother had lots of them, but fellow students at UMass-Dartmouth say he also hung out with some Russian speakers.

NPR: For Bombing Suspects, Question May Be Who Led Whom

Inside the backpack, they found fireworks, a jar of Vaseline and UMass-Dartmouth homework materials for classes in which Mr. Tsarnaev was enrolled.

WSJ: U.S. Charges Three More in Boston Marathon Case

When the backpack was later found, inside it was a UMass-Dartmouth homework assignment sheet from a class Tsarnaev was taking, the FBI said.

NPR: For 3, Bomb Suspect's Friendship Leads To Charges