Federal, state, and local investigators continue their search for clues this morning trying to figure out who planted two explosive devices near the finish line of the Boston marathon.
This morning, several blocks around the Boston marathon finish line remain closed, classified as a crime scene, investigators working around the clock to determine who's responsible for two deadly blasts.
A little more than four hours into the 117th Boston marathon, the race came to a chaotic and violent end.
Two explosions near the finish line, about 12 seconds and 50 yards apart, shattered windows and sent runners, spectators and officials scrambling for safety. "People were just running, sprinting back. The runners were going the other way. There were people running crying," said one runner.
Dozens of the wounded were rushed to several Boston hospitals.
Among the dead, an eight year old boy.
Doctors say they are treating wounds from the blasts' impact and flying debris.
In an instant, they went from treating dehydration and blisters to things you'd see on a battlefield."Bone injuries, soft tissue injuries and vascular injuries to the lower extremities." said Dr. Peter Fagenholz Massachusetts General Hospital.
The FBI is leading the investigation, and evidence collection teams have been brought in from New York.
At the white house, President Obama vowed it will be a swift and thorough search for whomever planted the devices. "we will find out who did this, we will find out why they did this. Any responsible individuals, any responsible groups will feel the full weight of justice."
Police questioned a man who was injured and being treated in Boston Hospital, but investigators say he is not considered a suspect nor a person of interest.