National Guard soldiers guard a roadblock near the scene of a twin bombing at the Boston Marathon on April 16, 2013 in Boston, Massachusetts (Spencer Platt/Getty Images)
(WUSA9) -- During a press conference in Boston on Tuesday morning, officials say that no unexploded bombs were found at the Boston Marathon after two bombs went off on Monday. Officials know of no other threats to the city, according to Special Agent in Charge Richard DesLauriers.
Officials say that the scene is going to take several days to process. An ATF official said explosive specialists and forensic specialists continue to work at the scene. Boston police commissioner Ed Davis called the scene "the most complex crime scene we have dealt with in the history of our department." Commissioner Davis says police are working with the FBI to go through every frame of surveillance video in the area.
A heightened police presence continues in the area of the marathon. City officials encouraged Boston residents to have a heightened awareness of their surroundings and to report anything they believe is suspicious.
Officials are asking for the public's help in submitting any videos or photos from the area or information concerning the event that could help with the investigation. They are asking people with those videos or photos to call the FBI hotline. the Major Case Contact Center can be reached at 1-800-CALLFBI (225-5324). You can also submit tips online here: https://tips.fbi.gov/ Please include the time the photos or video were captured.
In the aftermath of the tragedy, Boston mayor Tom Menino said that city officials have received calls from all over the world, with people asking how they can help. He urged, "Let's continue to work together, let's give a helping hand to individuals who need it."
He commended law enforcement and emergency crews for their work, calling "the men and women who wear helmets, badges" heroes.
At the conference, Suffolk County District Attorney Daniel Conley stated that "what occurred in Boston was an act of cowardice." He added, "Make no mistake -- an act of cowardice cannot be justified or explained, it can only be answered."
Three people were killed, including 8-year-old Martin Richard, and more than 170 were wounded from the blasts. A doctor who was at the scene said a victim was maimed by something resembling ball bearings or BBs. On Tuesday morning, Massachusetts General Hospital officials said during a press conference that there were some sharp objects found in people's bodies that may have been from the bombs. The Associated Press reports that a doctor at Boston Children's Hospital said staff removed BB pellets and nails from children. Two children with serious leg injuries remained in critical condition at the children's hospital.
MGH officials commended their staff for their response. The chief of trauma surgery said doctors from all over MGH offered to help, volunteering to stay hours longer at the hospital, and doctors who were outside of the city flew back to offer their services. He also said one doctor who ran in the Boston Marathon who was dealing with dehydration came back to help.