The deadly bombs that struck the Boston Marathon on Monday were fashioned from large pressure cookers packed with nails and ball bearings and hidden in black bags on the ground, said FBI investigators and a U.S. official briefed on the investigation.
The construction of the devices, which killed at least three and injured more than 170, many of them gravely, showed signs of “training or knowledge,” the official said.
In addition, authorities told The Associated Press that they recovered a piece of circuit board they believe was part of one of the explosive devices, and also found the lid of a pressure cooker that apparently was catapulted onto the roof of a nearby building.
A task force of federal, state and local law enforcement authorities ramped up a huge investigation Tuesday, but officials said they had no suspects or motive. Federal authorities cleared the 20-year-old Saudi national who briefly was considered a “person of interest.”
Led by FBI bomb technicians, authorities are working painstakingly to rebuild the two bombs in an effort to determine their origin.
“This will be a worldwide investigation,” Richard DesLauriers, special agent in charge of the FBI’s Boston field office, said at a news conference. He added that agents will go “wherever the leads take us.”
SEE ALSO: Ex-bin Laden hunter says Boston bombing shows signs of sophistication, training
He said numerous fragments of what they suspect were pressure cookers and pieces of dark-colored nylon bags found at the blast sites have been sent to FBI bomb technicians in Quantico, Va., for examination.
A former FBI agent who led the hunt for al Qaeda mastermind Osama bin Laden said the bombing showed a “level of sophistication or training” in the construction and placement of the weapons that could complicate the identification of the culprits.
Jack L. Cloonan, who led the FBI’s bin Laden unit from 1996 to 2002, said the bureau’s evidence response is painstakingly sifting the rubble of the twin blasts for fragments of the devices. Even an exploded bomb can yield evidence, telltale signs of the device’s construction and materials that indicate its maker, Mr. Cloonan said.
The FBI on Tuesday said there were two devices and both detonated, dismissing early reports of other devices being discovered at the scene or around the city. The Department of Homeland Security said that while there is no indication to suggest that the events in Boston were part of a broader plot, “out of an abundance of caution,” the department continues to keep in place “enhanced security measures at transportation hubs, utilizing measures both seen and unseen.”
More than 24 hours after the attack, the Pakistani Taliban said in a Tuesday statement that they did not conduct the bombing, although they welcomed it.
Islamic extremist groups claimed responsibility for the last two bombing attempts on U.S. soil within 72 hours, said Ben Venzke, CEO of IntelCenter, which monitors and analyzes terrorist communications.
SEE ALSO: Third Boston victim was BU student from China
The Pakistani Taliban claimed the bungled 2010 attempted bombing of Times Square by Faisal Shahzad in less than 24 hours via video. Al Qaeda in the Arabian Peninsula claimed the 2009 Christmas underwear bombing attempt by Umar Farouk Abdulmutallab within 72 hours in a written statement.
Domestic terrorists such as anarchist or anti-government militia groups tend not to take credit.
Oklahoma City bomber Timothy McVeigh issued no claim for his attack. Atlanta Olympics bomber Eric Rudolph mailed claims to media organizations, but in the name of a fictitious group.
President Obama said America is strong and resilient in the face of the deadly explosions and won’t let “cowardly acts get in the way of our lives. … We’re going to uncover whoever was responsible.”
Amateur videos
Attorney General Eric H. Holder Jr. said the task force has begun conducting exhaustive interviews, analyzing evidence recovered from the scene, and examining video footage for possible leads. In addition, he said, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is providing bomb technicians, explosives assets and other substantial investigative support. The Drug Enforcement Administration and the U.S. Marshals Service also are providing assistance.
Former White House counterterrorism official Richard A. Clarke said the FBI will stitch together hundreds of hours of video camera recordings from private and public surveillance and traffic cameras, as well as recordings made by private citizens attending the race.
A former FBI official said the devices were designed to maximize horrific injuries.
“A pressure cooker packed with nails, that’s a very, very nasty bomb,” said Chris Swecker, former director of the bureau’s Criminal Investigative Division. He said agents will have a huge quantity of video material to analyze, including cellphone videos submitted by members of the public in response to the FBI’s appeal and material from surveillance cameras at banks and other businesses nearby.
“With the amateur videos [from the public], you have to do it manually,” he said, meaning “a bunch of agents will just have to sit down and watch it all.”
But with video from security cameras, digitally stored in a Web-compatible format known as IP, “it is much easier to sort, catalog and review,” looking for specific events or events in specific places, he said.
In a 2006 failed attempt to assassinate President George W. Bush in Tbilisi Georgia, a grenade thrown onto a stage failed to explode, Mr. Swecker said. The FBI legal attache at the U.S. Embassy used video shot by a U.S. citizen at the event to identify the perpetrator, who was then tracked down by Georgian authorities.
Enormous damage
The severity of many of the injuries in Boston underlined the enormous damage that can be inflicted by such homemade bombs, called “improvised explosive devices” or IEDs. Analysts said pressure cookers have been used in terrorist IEDs targeting U.S. troops in Afghanistan.
IEDS are “the easiest and safest way to kill numbers of people,” said Robert Liscouski, a retired senior Homeland Security official and career law enforcement officer.
“They have a stand-off capability,” he said, noting that IEDs can be set off by remote control through a cellphone, a radio device or a timer. “If you use a gun, you have to be there and you are unlikely to able to leave the scene.”
There are technical challenges to building a bomb from scratch, he said, but the organizational and technical resources for a bombing like the ones in Boston are “low-level,” he said, and most local government and law enforcement agencies in the United States “are not well enough equipped to detect and counter them.”
Striking a soft target like the marathon “is difficult … but not very difficult,” he said, and made easier by the nature of the target: a large public event, where authorities would have deliberately telegraphed to the public many of their security measures, such as street closings or checkpoints.
Mr. Liscouski noted the billion dollars a year spent during the height of the Afghanistan and Iraq wars to fund the Pentagon’s Joint Improvised Explosive Device Defeat Organization, and compared it with the funding for the Homeland Security Department’s office of bombing prevention, which has been cut from $20 million to $11 million a year.
In the wake of the Boston bombings, he said, those “numbers seem out of whack with where the threat is.”
The U.S. military developed “a lot of good knowledge, good skills and good technology that can transfer down to state and local” police forces, he said, “but it requires investment.”
Mr. Cloonan said no one should jump to conclusions.
“I’ve seen these devices [in Boston] called rudimentary, crude, unsophisticated. … I never like to use those terms,” he said.
’Very smart’
“These devices were powerful enough to shred limbs, lethal enough to kill people. … The person or people that did this were very smart,” said Mr. Cloonan, who retired from the FBI in 2002 and now heads the special risks team at Red24, a security firm based in the United Kingdom.
Despite all the talk about bomb designs and explosive recipes on the Internet, Mr. Cloonan said: “It’s actually not easy to make a bomb [from scratch]. A lot has to go right” for it to work.
He said that by timing the explosions for a few hours into the marathon, the bomber ensured that the professional athletes would have long ceded the finish line to “ordinary Joes,” meaning that “media attention has pulled back and law enforcement naturally has the instinct to start to relax.”
The task force has cordoned off as a crime scene a square-mile area around the bombing sites.
As long as the attackers are still out there, they could strike again, said Mr. Liscouski, the retired senior Homeland Security official who is now a director of Implant Sciences Corp., a security technology firm. Investigators will be “working against the clock” to identify suspects “to prevent the next event,” he said.
Homeland Security is the lead federal agency for protection of targets nationwide, Mr. Liscouski said. “But the doers are at the local level,” where police and government agencies will have to start thinking about how they can improve the protection of potential soft targets in their communities.
• This article is based in part on wire service reports.
• Shaun Waterman can be reached at swaterman@washingtontimes.com.
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