While the investigation has yielded no results, with no one claiming responsibility, more details have emerged on the nature of the explosives.
According to a person close to the Boston Marathon investigation, the explosives were in 6-liter pressure cookers and placed in black duffel bags. The person, who spoke on the condition of anonymity, said investigators have some of the bomb components but did not yet know what was used to set off the explosives.
The statement echoes the Massachusetts General surgeon’s words that given the injuries they treated, “most of [the metallic fragments in the patients] were in the bomb.”
The General surgeon addressed the media Tuesday. He said that the shrapnel was consistent in size, and included nail-like fragments.
“There were people who had 10, 20, 30 of them in their body,” he said.
Earlier, FBI and Boston city authorities declined to comment on the nature of the explosives that were triggered 12 seconds apart in the late hours of the race, when most of the top runners had finished and ordinary participants were completing the event.
Massachusetts Gov. Deval Patrick stressed that “only two explosive devices were found yesterday”, rejecting reports that earlier suggested five explosives were found.
Addressing the public the morning after the tragedy, FBI, Boston city authorities and police said that they are still seeking public assistance, calling for witnesses to come forward.
“We are processing the most complex crime scene in the history of our department,” Police Commissioner Edward Davis said.
People who captured amateur photos and videos are being asked to submit their footage as it might help with the investigation into the double blasts which have killed three and left more than 170 people injured.
“We have received voluminous tips over the last 18 hours since the incident,” FBI special agent in charge, Rick DesLauriers said.
The police gave no details on the going investigation. Police called on citizens to be patient as they will see a “continued, heightened police presence”.
Police are searching the 26.2 mile route of the race. Currently the crime scene has been scaled down to12 blocks. FBI special agent in charge, Rick DesLauriers, said that there is currently “no known physical threat.”
US Homeland Security Secretary Janet Napolitano said Tuesday there was no indication that the bomb blasts in Boston were part of a broader plot.