Monday's bomb attack on the Boston Marathon showed a "level of sophistication or training" in the construction and placement of the weapons that could complicate the identification of the culprits, said a former FBI agent who led the hunt for Osama bin Laden.
Jack L. Cloonan, who led the FBI's Osama bin Laden unit from 1996 to 2002, said that the FBI's evidence response team would have to painstakingly sift the rubble of Monday's twin blasts for fragments of the devices, which is why they have secured the scene.
Even an exploded bomb can yield evidence, tell-tale signs of the device's construction and materials that indicate its maker, Mr. Cloonan told The Washington Times.
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.
Mr. Cloonan said the evidence response team would have been at the scene since Monday, carefully locating, cataloguing and recovering bomb fragments. "They've got to be able to tell how [the bombs] were made and what of," he said.
Al Qaeda and other extremists "will take responsibility, if they did it," he said, but domestic terrorists such as anarchist or anti-government militia groups tend not to.
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.
The Pakistani Taliban claimed the bungled 2010 attempted bombing of Times Square by Faisal Shahzad in less then 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.
The Pakistani Taliban said in a Tuesday statement they did not conduct the bombing, although they welcomed it.
"No credible claim of responsibility has been identified yet," Mr. Venzke said in a statement.
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.
"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 U.K.-based security firm.
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."
Outside the "frozen zone" around the viewing stand, spectators could move freely and there "probably were hundreds of backpacks, including those left by runners" so someone carrying one or even two would be easily able to blend in, he said.
"They were smart enough to know all that, to have thought about it. That, to me, shows a level of sophistication or training," Mr. Cloonan said.
© Copyright 2015 The Washington Times, LLC. Click here for reprint permission.