WITH GWEN IFILL
FRIDAY, MAY 3 @ 9:00PM
Two students from Kazakhstan and an American teenager are charged with obstructing the police investigation into the April 15 bombing in Boston. All three are college friends of bombing suspect Dzhokhar Tsarnaev. Pete Williams of NBC News will have the latest on the international investigation and what the three friends told police about the 19-year-old bombing suspect.