Erin Burnett remembers the victims of the Boston marathon bombing terror attack.
An envelope that tested positive for the deadly poison ricin was addressed to the office of Senator Roger Wicker, Republican of Mississippi.
Chief congressional correspondent Dana Bash broke this news first on CNN and reports OutFront.
Family and neighbors are gathering at vigil tonight to remember the youngest victim of yesterday's bombings - 8 year-old Martin Richard.
The little boy was killed near the finish line as he was watching the marathon with his family.
His mother and 6 year-old sister were also injured by the blast.
Attending candelight vigil for 8 year old Martin Richard, one of the three who died in #BostonMarathon bombing. It's a very difficult time.
— Gary Tuchman (@GaryTuchmanCNN) April 16, 2013
CNN's Gary Tuchman is at the vigil tonight in Garvey Park.
New clues tonight about the explosive devices that killed three people and injured more than 180 at the Boston Marathon. The FBI says the bombs were most likely made using pressure cookers filled with shards of metal, nails and ball bearings.
It's believed the bombs were placed inside dark-colored duffel bags and placed near the finish line.
OutFront tonight: Ray Lopez, a former member of the FBI Hazardous office for 22 years.
New details on the devices that killed three people and injured at least 183 more at Monday's Boston Marathon.
House Homeland Security Chair, Congressman Mike McCaul told reporters today that it was quote, "most likely gun powder" that was used in the devices.
OutFront tonight: Rep. Mike McCaul (R-TX).