Could the Boston Bombers Have Been Stopped?

FBI(NEW YORK) — A year after the Boston Marathon attacks, there are troubling new questions about whether the bombings could have been thwarted and how two brothers from Chechnya learned to allegedly execute their terrorist attack so efficiently, officials tell ABC News.

Dzhokhar Tsarnaev, 20, and his brother Tamerlan, 26, are accused of detonating two bombs at the finish line of the Boston Marathon, killing three people and injuring more than 260 others a year ago on Tuesday. Tamerlan was killed in a shootout with police days after the bombing, but Dzhokhar was arrested and now sits in jail, isolated from other inmates and awaiting trial. He has pleaded not guilty.

But many current and former senior officials who have investigated the tragedy told ABC News that they question whether the brothers might have been neutralized by a more thorough FBI investigation before the attacks, and whether as bombmaking novices they had to have had help in allegedly building several different types of sophisticated devices, which they used more successfully than any other homegrown terrorists since 9/11.

“I do think that had we taken a second look, we could’ve stopped this,” Rep. Michael McCaul, R-Texas, Chairman of the House Committee on Homeland Security, told ABC News.

According to court documents, the inspector general’s report and sources briefed on the federal investigation of the attacks, the FBI and prosecutors contend that both Tsarnaev brothers learned to build their improvised explosive devices using pressure cookers as well as three pipe bombs by downloading instructions off the Internet.

But ABC News has learned that many within the FBI, law enforcement and counter-terrorism strongly disagree that they could have become good enough to make the improvised explosive devices (IEDs) from online how-to’s and suspect an expert taught or instructed Tamerlan on the craft of bombmaking while he was overseas in 2012.

“For a ‘novice’ pair of IED builders and emplacers, for them to work as they did, to be effective, that indicates to me a level of sophistication that they received some sort of training from somewhere,” retired Army Lt. Gen. Mike Barbero, former director of the Joint IED Defeat Organization, told ABC News. Barbero headed the organization at the time of the marathon attacks.

Prosecutors allege that the Tsarnaevs got recipes for the pressure-cooker IEDs — common on battlefields in Afghanistan — and “elbow” pipe bombs from online instructions published four years ago in Inspire, a terrorist magazine published by al Qaeda’s affiliate al Qaeda in the Arabian Peninsula (AQAP). AQAP offered wannabe jihadis instructions for both types of IEDs under the headline, “Make a bomb in the kitchen of your mom.”

But an analysis of the bombs done by FBI technicians at the Terrorist Explosive Device Analytical Center (TEDAC) in Quantico, Va., in late April 2013 found that the bombs in Boston had a much more sophisticated design than that in the online magazine, including differences in the initiators, power source and switch/trigger, which utilized a toy car remote control. Inspire never contained instructions for that type of switch/trigger used to remotely set off the IEDs, but had directions for a different type using a motorcycle remote starter.

“While the RC concept is similar, TEDAC assesses INSPIRE would not provide an individual with the appropriate details to translate these instructions for use with RC toy car components. Such construction would likely require previous knowledge of, or additional research into, RC toy car circuitry,” a TEDAC analysis document said.

“They didn’t get it just from online and definitely didn’t get it just from reading Inspire magazine. So where did they get this training and how did they acquire the skill?” Barbero said.

The indictment of Dzhokhar Tsarnaev alleges that he and Tamerlan “armed themselves with five IEDs, a Ruger P95 9mm semiautomatic handgun, ammunition for the Ruger, a machete and a hunting knife” before engaging in their April 19 shootout with Watertown police. The bombs included a pressure cooker IED, three pipe bombs and a Tupperware tub filled with black powder and a fuse — they exploded all but the tub during a firefight. The gun was bought illegally from a suspect still under investigation in another state, a law enforcement official told ABC News.

They also threw small black powder grenades called “crickets” at police during a car chase, sources said.

Allegedly creating and detonating such different IEDs put the Tsarnaevs in a class by themselves as post-9/11 homegrown terrorists, who typically have tried to perfect just one IED design and have rarely succeeded in detonating any at all, officials said.

“It is absolutely a major unanswered question of how they got that good and whether they had assistance of some kind,” a senior counter-terrorism official told ABC News last week. “They had a better success rate than AQAP’s master bombmaker al-Asiri,” who created the underwear and printer cartridge bombs snuck aboard airplanes, which failed to detonate.

McCaul’s staff recently completed a year-long investigation of the Boston attacks. It found federal counter-terrorism officials failed to alert Massachusetts law enforcement that Russia’s security services in 2011 informed the FBI and later CIA that Tamerlan Tsarnaev and his mother Zubeidat Tsarnaeva were suspected of being radicalized Islamists.

“I think it’s very clear today, after the investigation we conducted and the investigation the inspector general conducted of the intelligence community and the FBI that that foreign connection is real and that he was over there meeting with extremists,” McCaul said. “He was greater radicalized and it’s very likely he did receive training.”

An intelligence community inspector general report released last week revealed that the FBI only interviewed Tamerlan and his parents in Boston but not other associates or an ex-girlfriend he had assaulted. The FBI found nothing to support the Russian claim — which stemmed from an intercepted phone call by Russian spy services.

“Now in fairness to the FBI, the Russians had information they didn’t share with the FBI after their warning came in and that’s unfortunate,” McCaul said. McCaul and other officials were also quick to state that they see no evidence the Tsarnaevs were acting on orders of a foreign terrorist group. But extremists likely offered Tamerlan expertise, he agreed.

Tamerlan Tsarnaev soon faded as a counter-terrorism priority and he was able to travel to Chechnya and Dagestan in January 2012. He returned in July without facing further investigative scrutiny — partially because his name was misspelled in a security database — and soon began posting jihadi material including videos on YouTube.

FBI and Justice Department officials declined comment, citing Dzhokhar Tsarnaev’s upcoming death penalty trial.

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