Boston bombs possibly pressure-cookers full of shrapnel

  • AFP, Washington
  • |
  • Updated: Apr 17, 2013 10:37 IST
  • Boston Marathon

    Two women sit with their dog near the scene after two explosions interrupted the running of the Boston Marathon in Boston, Massachusetts. REUTERS  

  • Oklahoma Christian

    Shane Magness, a student at Oklahoma Christian University, bows his head in prayer for the victims of the Boston Marathon bombing, at the Oklahoma City ...

  • Minnesota Twins

    The Minnesota Twins stand during the National Anthem following a moment of silence to honor the victims of the Boston Marathon bombing before the game ...

  • US flag flies

    A US flag flies at half staff on the US Capitol on Capitol Hill in Washington, DC. AFP photo

  • Idaho

    Marion Kaucic participates in a candle light vigil at Friendship Square in Moscow, Idaho. Local runners held the vigil and a 2.62-mile run in support ...

  • Fans take

    Fans take a moment of silence in honor of the Boston Marathon explosions before the NHL game between the Phoenix Coyotes and the San Jose ...

  • Boston Marathon

    Police and federal officials exit an apartment complex at 364 Ocean Avenue with a possible connection to the earlier expolsions during the Boston Marathon in ...

  • Counter Terrorism

    A Los Angeles Sheriffs Counter Terrorism Unit officer carries an AR-15 assault rifle, as he patrols the entrance to Union Station in Los Angeles. The ...

  • Boston Common

    Police officers detain a handcuffed suspect following a search of the Boston Common area located about a mile from the Boston Marathon finish line where ...

  • Boston Marathon

    Unclaimed finish line bags are viewed near the scene of a twin bombing at the Boston Marathon, in Boston, Massachusetts. AFP photo

The deadly explosives detonated at the Boston Marathon were homemade devices full of nails and metal fragments, possibly packed into kitchen pressure cookers, US officials said.

A day after an attack that left three dead and more than 180 wounded, the FBI said the crude bombs may have employed pressure cookers, a common tactic seen in attacks from Afghanistan to France since the 1990s.

"Among items partially recovered are pieces of black nylon, which could be from a backpack, and what appear to be fragments of BBs and nails, possibly contained in a pressure cooker device," Rick DesLauriers, head of the FBI's Boston office, told reporters.

Both of the bombs had been placed in a dark colored nylon bag or backpack, DesLauriers said.

Still image taken from video courtesy of NBC shows an explosion at the Boston Marathon. Reuters

Bomb specialists and dog teams combed the scene at Boylston Street, the finish line of the city's renown marathon, while authorities sent blast evidence to the FBI's laboratory in Quantico, Virginia for a thorough analysis.

"The scene is going to take several days to process," said Gene Marquez, acting special agent in charge of the Bureau of Alcohol, Tobacco, Firearms and Explosives office in Boston.

Police, who were still unsure if the attack had domestic or foreign roots, said the area had been swept twice before the race and no explosives were found.

Emergency workers and doctors who treated the victims said the bombs appeared to have sent nails, ball bearings and metal fragments flying, causing injuries mostly to the lower part of the body, and forcing amputations for some patients.

"There are a variety of sharp objects that we found in their bodies," said George Velmahos, chief of trauma surgery at Massachusetts General Hospital.
"Probably these bombs had multiple metallic fragments in them and we removed pellets and nails," he said.

The devices were "placed probably low on the ground, and therefore lower extremity injuries are to be expected," Velmahos added.

The relatively limited scale of the two explosions and the white smoke that rose up afterward seemed to rule out military-type plastic explosives such as C4 or Semtex, which tend to produce more powerful detonations with black smoke, experts said.

Speculation focused on what type of improvised devices had been used, possibly a pipe bomb or an acetone peroxide explosive, which are both relatively easy to make and to conceal.
 
An acetone or TATP explosive was employed in the 2007 London bombings, an attack on the 1996 Olympics in Atlanta and a failed attempt by "shoe bomber" Richard Reid in December 2001 to detonate a device on a Miami-bound flight.

The organic peroxide, however, is unstable and sensitive to any heat and friction, with bomb-makers often suffering injuries when preparing the devices.
Bomb-making manuals appearing in jihadist online forums, including one produced by Al-Qaeda's branch in Yemen, often suggest using pressure cookers, according to SITE Intelligence Group, which monitors extremist groups' online messages.

Factbox: Key facts about the Boston Marathon

In 2010, the first issue of an English-language magazine by Al-Qaeda in the Arabian Peninsula (AQAP), the terror group's Yemeni affiliate, included an article explaining how to make an explosive with a pressure cooker and shrapnel.

The article was titled "Make a Bomb in the Kitchen of Your Mom" and had a photo of a backpack concealing the explosive.

White supremacists in America took note of the article and one online forum, Stormfront, called the how-to manual "highly recommended reading," according to SITE.

Pressure-cooker explosives were behind a wave of attacks in France in 1995 and in 2003, the Department of Homeland Security issued a bulletin warning authorities to be on the lookout for extremists using pressure-cooker bombs.

The bulletin said it was a "technique commonly taught in Afghan terrorist training camps" and that pressure-cooker bombs were used in attempted attacks or plots in India and Algeria, as well as an assault in Nepal.

"Typically, these bombs are made by placing TNT or other explosives in a pressure cooker and attaching a blasting cap at the top of the pressure cooker," the bulletin said.

Boston blasts set off global terror probe, but few clues
Nothing will stop 78-year-old runner
Indian-origin doctor turns saviour
Indian-origin marathoner, family escape Boston twin bombings

 

also read

The entire country is behind the people of Boston: Obama

blog comments powered by Disqus