In his new book, The Terror Factory: Inside the FBI's Manufactured War on Terrorism, investigative journalist Trevor Aaronson analyzes 10 years of terrorism cases that were prosecuted in the United States after Sept. 11.

By assembling a database of the cases and going through court records, he concluded that the FBI, which receives $3 billion per year for counterterrorism, is "the organization responsible for more terrorist plots over the last decade than any other."

Rather than stopping actual terrorist attacks, like the Boston bombing, the FBI focuses significant resources on using informants and sting operations to entrap would-be Islamic terrorists who "never could have obtained the capability to carry out their planned violent acts were it not for the FBI's assistance," he writes in his book.

Aaronson, the co-director of the Florida Center for Investigative Reporting, spoke to CBC News by phone from Florida.

CBC News: After assembling your database of terrorism cases in the United States, what did your analysis turn up?

Trevor Aaronson, author of 'The Terror Factory,' speaks at at Columbia Law School's Human Rights Institute on Jan. 31. (David Felix Sutcliffe)

Trevor Aaronson: What the database looked at was a little more than 500 defendants who'd been prosecuted on international terrorism charges in the decade after 9/11. Of the 500 cases, you could expel about half of them as being not specifically related to terrorism. These were cases where someone was charged with immigration violations, or lying to the FBI and that the federal government alleged that they had some sort of connection to terrorism, however tangential that might have been. But none of those cases involved people who were specifically engaged in a plot of any kind.

And then, of the 250 or so that are left, you can really only point to five or so cases that involved someone who posed a significant threat, that was dangerous on their own, like Faisal Shahzad, for example, who delivered a car bomb to Times Square in 2010 that, fortunately, didn't go off. Or Najibullah Zazi, who came close to attacking the New York subway system, or the shoe bomber and the underwear bomber. But really, roughly those five cases are the ones of the 500 that you can point to and say, "those were dangerous guys."

By contrast, there were about 150 defendants who were caught in terrorism sting operations.

In these sting operations the FBI provided everything that these men needed. They provided the weapons, the transportation and in some cases even the idea itself. These 150 defendants were people that the FBI alleged could one day, possibly, be terrorists. And these sting operations were meant to pre-empt them from becoming terrorists.

I argue in my book, in all of these cases, the evidence suggests that these men became terrorists only because the FBI provided them with the capability. These were incompetent men who were only capable of the most minor crimes.

CBC News: Tell me more about the portrait of these 150 men caught up in the terrorist stings.

The people that are caught in these terrorism sting operations are Muslims who are living on the fringes of those communities. In many cases they are mentally ill. In other cases that are economically desperate, they're poor and the informant offers them inducements, such as money, assets. For example, an informant in a case outside New York City offered one man $250,000 and to buy him a barbershop if he moved forward in a plot. In other cases you have people who are really just losers in life, don't have many friends.

The informant has an incentive to find people who can be targeted in these sting operations, because they can make thousands of dollars in these operations. At the same time, then they are targeting people who are easily manipulated and easily brought in to these sting operations.

But in these cases, it's the informant and the FBI that are providing the means, providing the weapons. Left to their own devices these men are unlikely to have ever been able to acquire these weapons.

CBC News: As we learn more about Tamerlan Tsarnaev, one of the alleged Boston bombers, who apparently was not caught up in an FBI sting, but known to the FBI, it sounds like he could have fit in with composite of the characters in your book. What's your thinking on that?

Aaronson says that Tamerlan Tsarnaev, unlike most the men prosecuted on terrorism charges after getting ensnared in FBI sting operations, allegedly showed that he could put together a bomb. (Julia Malakie/The Lowell Sun/Associated Press)

That's right. But the difference between Tamerlan Tsarnaev and the men caught in sting operations is the men caught in sting operations often are these loudmouths who never have the ability to go and make the bomb themselves, or are really more talk than action. So these FBI sting operations are able to easily draw out these people who are on the fringes of these communities saying kind of loudly, "I want to get involved in terrorism."

Instead, the Tamerlan Tsarnaevs and the Faisal Shahzads, Nidal Hassans, they're going undetected by the FBI because they're not stupid enough to go out and start talking to people about these kinds of things. That's the primary difference.

Another difference: Tamerlan Tsarnaev allegedly was able to show that he could put together a bomb. The cases that the FBI ultimately prosecuted for terrorism show that the defendants in these cases aren't even capable of that.

CBC News: The FBI would say they have excellent stats on convictions, even a high rate of guilty pleas, and one FBI source — J. Stephen Tidwell, the FBI's executive assistant director — said to you, "What do you do? Wait for these guys to figure it out themselves?" So what's wrong with the FBI using informants and sting operations, given that?

Let me back up. I'm not against the use of informants, the use of surveillance, when it's justified. I think we should be looking at people as possible threats. If there's reason to believe that they're going to be involved in terrorism, then we should assign informants and we should figure out what they're doing.

I think where the FBI crosses the line is when it empowers, through these sting operations, people who the evidence shows and the intelligence shows aren't able to commit the acts of terrorism now and most likely even into the future.

Mohamed Osman Mohamud, a Somali-American was found guilty in January of attempting to bomb a Portland, Ore. Christmas tree-lighting in 2010. Aaronson says the FBI thought he would be susceptible to their advances and set up what turned out to be a sting operation. (Mauthnomah County Sheriff's Office/Associated Press)

Publicly, the FBI says they're using these sting operations to keep the public safe. But if you look at the evidence in a lot of these cases, it's clear that there's real pressure to make cases.

There was a case in Portland, Ore., involving a man who plotted in a sting operation to bomb a Christmas tree lighting ceremony. In his trial, some FBI emails came out where they talk about how because he smoked pot and because he was kind of a distant guy and a loser that he's really going to be susceptible to their advances.

For them to go to him and offer him the opportunity to commit his crime, that really contradicts the FBI's public statements on these cases, which are to say, "We only target people who we believe are a threat." Instead, that email suggests, here are some counterterrorism agents and they are looking to make some cases. That's a human thing that we can all understand, too.

If you are a counterterrorism agent at the FBI, you are reviewed based on the number of cases that you bring, the number of terrorists that you bring. That's certainly what we saw in Boston. In January 2011, they investigated Tamerlan Tsarnaev and they said, "No problem, we don't see any reason to be concerned."

Rezwan Ferdaus of Ashland, Mass., was arrested in 2011 in an FBI sting operation that involved sending a remote-controlled model plane packed with explosives into the dome of the U.S. Capitol Building. (Courtesy WBZ-TV Boston/Associated Press)

At the same time, that same month, they launched a sting operation against Rezwan Ferdaus, who had this fantastical idea of flying a remote-controlled airplane loaded with grenades into the U.S. Capitol Building. The trouble was, not only was that idea just ridiculous, he didn't have any money. And so the FBI gave him money to buy the airplane, they gave him the fake C4, everything he needed to move along in his plot and then they charged him with attempting to destroy a federal building and providing material support to terrorists.

What this shows, in a very small way, in the Boston area, how they let go someone who really was a threat in order to pursue a case against someone they could easily move along in a terrorism sting operation and result in a prosecution that they could bring to the public and say, "Hey, look at us, this is us keeping you safe."

[Ferdaus was arrested on Sept, 28, 2011. He pleaded guilty and received a 17-year prison sentence.]