Investigators believe at least one of the two bombs in Boston was made with a pressure cooker, according to law enforcement and intelligence officials.
Rich DesLauriers, FBI special agent in charge in Boston, said at an afternoon news conference that investigators found pieces of black nylon from two backpacks and possible fragments of pressure cooker metal. He said they were all being sent to the FBI lab in Quantico, Virginia.
A federal official who asked not to be identified because he was not authorized to speak publicly said evidence recovered at the scene of the marathon explosion suggests the ingredients for one of the two bombs were hidden in a metal pressure cooker tucked inside a backpack. Although no pressure cooker parts have yet been found for the second pump, located a block and a half away, it had a similar design, he said.
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The law enforcement official added that these types of devices would “most likely” have been activated with the use of timing devices and circuit boards instead of remote cell phones
.
“We’re leaning toward timing devices,” he said. “With only 10 seconds between the two explosions, that might not have been enough time to trigger both explosions with a cell phone.”
He also said that although pressure cookers are often used in the Middle East, they are also highlighted in Internet bomb-making instructions in this country as a receptacle to hold a large amount of shrapnel. In Boston, many of the dead and wounded were sprayed with metal fragments, small nails and ball bearings.
Shrapnel is usually glued or fixed to the inner lining of the kitchen, and then the rest of the receptacle is filled with flammable material. When the bomb comes on, it bathes the area with explosive shrapnel.
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explosion
Fragments of the blast have been found embedded in the sides of nearby buildings and roofs, a spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives
said.
“That gives you an idea of the extent of the power of the explosion,” the spokesman said. “You could see how devastating it was.”
DesLauriers said the FBI has received more than 2,000 leads. But the range of possible suspects is “open.”
FBI analysts are reviewing more than 10 terabytes of data for clues as to who might have placed the bombs near the finish line. The data includes call logs collected by cell phone towers along the marathon route and surveillance footage collected by city cameras, local businesses, gas stations, media outlets and bystanders who volunteered to provide their videos and snapshots, the federal law enforcement source said.
The FBI has brought analysts from field offices across the country to Boston to view and record hundreds of hours of video, he said.
In a 2010 publication, Yemen-based al Qaeda members encouraged would-be terrorists in the United States to use a pressure cooker and other household items to build a bomb.
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“
Make a bomb in your mom’s kitchen” was the headline of the instructions in a brilliant English-language publication called Inspire magazine that was published in Internet chat rooms.
The eight-page article said that a “lone mujahid,” or holy warrior, would not arouse suspicion by purchasing items readily available to make the bomb. Ingredients included granulated sugar, matches, small nails, and a 2-inch iron pipe section or pressure cooker. The bomb could be made in a day or two, the instructions said, “to kill at least 10 people.”
“Pressurized cooking is the most effective method,” he said. The bomb-making recipe, illustrated with color photographs, recommended using a 9-volt battery and a cracked light bulb from a string of Christmas lights to turn on the explosive and an alarm clock as a trigger. The article is signed “AQ chef”.
“We are transmitting our military training directly to their kitchen to relieve them of the difficulty of traveling to us,” he said.
“This is an explosive device, so be careful during preparation and handling,” it said. The author recommends that the bomb manufacturer wear gloves to avoid leaving fingerprints.
FBI investigators
will likely go to stores in the Boston area to check pressure cooker sales records, said David C. Gomez, a former FBI counterterrorism supervisor
.
“People make bombs out of what’s available,” Gomez said in an interview. If it was a pressure cooker, that in itself is a little unusual,” he said.
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@ByBrianBennett
