Martin Richard .... the 8-year-old boy who was killed in the Boston Marathon bomibngs. Photo: WHDH.com Source: Supplied
Many of the wounded were rushed to triage in wheelchairs kept at the marathon finish line to assist exhausted runners. (AP Photo/The Boston Globe, David L. Ryan) Source: AP
A CANDLE has been lit in front of the home of the young boy killed in the Boston Marathon bombing, as his mother and sister remain in hospital.
Martin Richard, 8, of Dorchester, was at the marathon to watch his father race. He was standing near the finish line, waiting to give his dad a hug.
Martin's mother, Denise, is in hospital with "grievous injuries" and is believed to have had surgery for a brain injury. The Times of London reports. His six-year-old sister lost a leg in the blast. Her name has not been released.
The status of his father, William, has also not been released. Boston's 7 News TV station released a photo of Martin on their WHDH.com website.
Neighbours remembered Martin as a vivacious boy who loved to run and climb. A single candle was lit in front of their house and a single word was written on the sidewalk: Peace.
Peace is written on the sidewalk in front of the Richard house in the Dorchester neighbourhood of Boston. Martin Richard, 8, was killed in Monday's bombing at the finish line of the Boston Marathon. Picture: Michael Dwyer Source: AP
The news of what's happened to Martin's family comes as FBI agents lead a massive manhunt for those responsible for the twin blasts that unleashed murder at the Boston Marathon.
Police swooped on a flat in the Boston suburb of Revere with reports the search was linked to the co-ordinated explosions set off 12 seconds apart at 2.50pm (4.50am AEST), tearing through crowds near the finish line in the city's Boylston St.
The roommate of the Saudi Arabia man whose apartment was searched told the Boston Globe he doubted his roommate was involved,
"I don't think he could do that,'' he said.
The roommate said the 20-year-old man was a devout Muslim who was attending a Boston area English language school and he had last seen him on Sunday.
At a news briefing about 11.40pm AEDT Massachusetts Governor Deval Patrick said no unexploded devices were found on the streets of Boston after the initial explosions, despite earlier reports otherwise.
"It's important to clarify that two and only two explosive devices were found yesterday," Mr Patrick said.
"Other parcels - all other parcels in the area of the blast have been examined. No unexploded bombs. No unexploded explosive devices (were) found."
As it happened: The story as it broke and developed
A photo of one of the Boston Marathon explosions as it happens. Photo: Dan Lampariello / DobsonAgency Source: Supplied
FBI Special Agent In Charge Richard DesLauriers said there were "no known additional threats" to the city.
Authorities were also looking for amateur video and photographic evidence that could give clues to who set off the bombs.
Police commissioner Ed Davis said it was the most complex crime scene in history of the department.
He said 176 victims came to hospitals around Boston, and 17 of those were in a critical condition. Surgeons at Massachusetts General Hospital said some of the injuries suffered were consistent with the bombs being packed with shrapnel.
US Defence Secretary Chuck Hagel called the bombing a "cruel act of terror".
Mr Hagel said any event with explosive devices is clearly an act of terror and promised that a thorough investigation will determine whether the perpetrators were foreign or domestic.
The blasts knocked spectators and at least one runner off their feet, shattered windows and sent dense plumes of smoke rising over the street and through the fluttering national flags lining the course.
"They just started bringing people in with no limbs," said runner Tim Davey, of Virginia. He said he and his wife, Lisa, tried to keep their children's eyes shielded from the gruesome scene inside a medical tent that had been set up to care for fatigued runners, but "they saw a lot."
American news agencies reported a Saudi man seen running from the area had denied any involvement in the bombings while there were also reports police were searching for a man with dark skin and a black hooded shirt seen carrying two backpacks before the blasts.
"I started running toward the blast. And there were people all over the floor," Rhode Island police officer Roupen Bastajian said.
"We started grabbing tourniquets and started tying legs. A lot of people amputated. ... At least 25 to 30 people have at least one leg missing, or an ankle missing, or two legs missing."
A woman who was near the second bomb, Brighid Wall, 35, said that when it exploded, runners and spectators froze, unsure of what to do. Her husband threw their children to the ground, lay on top of them and another man lay on top of them and said, "Don't get up, don't get up."
She said she saw six to eight people bleeding profusely, including one man who was kneeling, dazed, with blood coming down his head. Another person was on the ground covered in blood and not moving.
"My ears are zinging. Their ears are zinging. It was so forceful. It knocked us to the ground."
US President Barack Obama vowed: "We will find out who did this. Any responsible individuals, any responsible groups, will feel the full weight of justice."
Prime Minister Julia Gillard branded the blasts "brutal and senseless."
Early reports up to seven bombs had been planted along the route were dismissed, but two unexploded devices were reportedly found by police, one just past the finish line of the event scheduled on the Patriots' Day holiday which commemorates the first battles of the American Revolution.
More than 150 Australians competed in the race, Jeff Hunt finishing hours before the bombings in eighth place and Kurt Fearnley fifth in his wheelchair category.
Indigenous runner Emma Cameron, who was 1km from the blasts and became separated from champion mentor Rob De Castella, was deeply traumatised, a spokeswoman said.
The blood-stained feet of a man hang from an ambulance outside a medical tent located near the finish of the Boston Marathon. (Photo by Jim Rogash/Getty Images) Source: Getty Images
The horror was captured by cameras trained on the finish line.
As people ran away from the blasts, some bystanders could be seen racing towards the scene.
They demolished a spectator fence by hand to allow medical personnel to get to victims, one woman raided a shop of yarn to stem the blood flow from victims' horrific leg injuries.
In other selfless acts, runners offered to give blood for the victims and doctors and nurses recalled themselves from their public holiday to operate on victims.
More than 17,500 of the 23,326 competitors had finished when the bombs detonated.
The event had also been dedicated the 26 victims of the Sandy Hook school massacre.
Afghanistan and Iraq veteran Captain Thom Kenney told CNN the timing was "horrible."
"The majority of people who were coming through had worked to raise hundreds to thousands if not millions of dollars for charities and good causes and those were the runners coming through at the time and their families and friends were supporting them coming through," he said.
"You've got this huge community effort trying to do good in the world in general and you see something horrific like this happen."
President Barack Obama talks on the phone with FBI Director Robert Mueller to receive an update on the investigation. (Photo by Pete Souza/The White House via Getty Images) Source: Getty Images
James Brennan said casualties were brought into the store where he works and that life-saving acts had been performed by bystanders.
"There was a woman grabbing spools of yarn in our store, wrapping people, cutting off the circulation so people wouldn't bleed out."
"It was really just a spectacle of how people came together."
Governor Patrick paid tribute for the "extraordinary kindness" shown by marathon spectators.
A White House official, said the attack was being treated as an act of terrorism, although Mr Obama, speaking from the White House, pointedly avoided using the words "terror" or "terrorism," saying officials "still do not know who did this or why."
As the FBI took charge of the investigation, authorities shed no light on a motive or who may have carried out the bombings, and police said they had no suspects in custody. Officials in Washington said there was no immediate claim of responsibility.
WBZ-TV reported that law enforcement officers were searching an apartment in the Boston suburb of Revere. Massachusetts State Police confirmed that a search warrant related to the investigation into the explosions was served Monday night in Revere but provided no further details.
Some investigators were seen leaving the Revere house early carrying brown paper bags, plastic trash bags and a duffel bag.
At Massachusetts General Hospital, Alasdair Conn, chief of emergency services, said: "This is something I've never seen in my 25 years here ... this amount of carnage in the civilian population. This is what we expect from war."
Boston Police Commissioner Edward Davis asked people to stay indoors or go back to their hotel rooms and avoid crowds as bomb squads methodically checked parcels and bags left along the race route. He said investigators didn't know precisely where the bombs were planted or whether they were hidden in mailboxes or trash cans.
He said authorities had received "no specific intelligence that anything was going to happen" at the race.
The Federal Aviation Administration created a no-fly zone over the site of the explosions, and briefly ordered flights bound for Boston's Logan International Airport held on the ground at airports around the U.S.
Runners in the medical tent for treatment of dehydration or other race-related ills were pushed out to make room for victims of the bombing.
Medical responders run a badly injured man past the finish line. Picture: AP Source: Supplied
Cities worldwide stepped up security following the explosions.
In Britain, police said they were reviewing security plans for Sunday's London Marathon, the next major international marathon. Thousands of people compete in the London Marathon every year, thronging the city's streets. London is also considered a top target for international terrorists.
A London Metropolitan Police spokesman confirmed Monday that police are working with marathon officials to review security plans for Sunday's event. The London race's chief executive, Nick Bitel, expressed shock and sadness about the situation in Boston, saying "it is a very sad day for athletics and for our friends in marathon running."
In New York City, police spokesman Paul Browne said that critical response teams are deployed around the city. Officials were stepping up security at hotels and other prominent locations.
