We've learned that Russia warned not just the FBI, but also the CIA about one of the Boston bombing suspects. So what happened to the follow-up?
Meanwhile thousands turned out for a memorial in honor of fallen MIT police officer Sean Collier. Among the mourners, Vice President Joe Biden who slammed the accused bombers, calling them, "two twisted, perverted, cowardly, knock-off jihadis."
CNN's Miguel Marquez reports.
Fulll coverage of Boston's recovery and the bombing investigation at HLNtv.com/BostonBombings.