In September of 2009, 24-year-old Najibullah Zazi used the training he learned at al-Qaeda camps in Pakistan to make nearly two pounds of highly volatile explosives. Zazi and his two childhood friends from Flushing, Queens, were planning on detonating suicide vests on the 3, 4, and 5 trains during rush hour. Zazi and the explosives made it past a bomb-sniffing dog on the George Washington Bridge, while the FBI agents and NYPD detectives that comprise the Joint Terrorism Task Force scrambled to figure out Zazi's plan. Why didn't the NYPD's Intelligence Division, the secretive, autonomous arm of the department that conducted sweeping and unprecedented surveillance of Muslim communities in New York, know anything about Zazi's plot?

This real-life narrative provides the basis for a new book by two AP reporters, Enemies Within: Inside the NYPD's Secret Spying Unit and Bin Laden's Final Plot Against America. Matt Apuzzo and Adam Goldman shared the Pulitzer Prize for their reporting on the NYPD's covert Muslim spying program, and their book offers a comprehensive look at the Intelligence Division and its leader, former CIA deputy director David Cohen, and a fascinating, deeply-sourced account of how our government responds to the threat of terrorism. "Enemies Within" opens with a quote from Voltaire on "internal security," but could just as easily have quoted a senior NYPD official from the book: "Desperation breeds novel ideas."

We recently spoke with Apuzzo and Goldman about City Hall's involvement with the Intelligence Division, why the NYPD has recalibrated its application of stop & frisk but not Muslim surveillance, and how flag burning can put you in police crosshairs.

The main thrust of the book seems to be that the NYPD's own Intelligence Division, which is designed to preemptively pick up on terrorism threats, not only failed to do that in one of the most serious threats to New York City since 9/11, but it also may have hindered that investigation.

MATT APUZZO: The point we were trying to make was that the Intel Division was designed to stop a plot like Zazi's. For all the information they collected on innocent people—people who were never charged—and for all the political and religious speech that was put into police documents, when it mattered most, this unit didn't detect the plot it was designed to detect.

I say "hindered" because one of the Intel Division's informants tipped off Zazi, which could have blown the whole investigation.

ADAM GOLDMAN: That's just emblematic of the friction between the JTTF and the Intel division, because Cohen's philosophy is: I'm just going to go at it alone. Whether it was Zazi or Bryant Neal Vinas or whether it's that guy Shehadeh, any number of examples where the Intel division doesn't let the JTTF—which is the primary vehicle with which our federal government investigates terrorism in this country—doesn't let them know what's going on, it causes problems. They don't deconflict. That's the issue at hand.

One of Intel's major strategies was "Zone Defense." Can you explain what that means?

APUZZO: The idea of Zone Defense is that we're gonna monitor the many to find the few. It's what we're now hearing from the NSA: In order to find a needle in a haystack you need a haystack. What NYPD Intel did was they went looking for what were some of the common elements of people who later became terrorists. They looked and said, "Well OK, these were people who joined student groups. Some of them grew their beard or they shaved their beard or they went to a mosque or they withdrew from a mosque or they found a spiritual leader or they became more spiritual in their views."

Their justification was, "Look, if we're in the mosques, if we're in the student groups we have a better chance of catching or spotting the next terrorist before he becomes a terrorist." Or maybe even before he knows he's going to become a terrorist. The NYPD's goal was to intercept them in the process even before they knew they wanted to become a terrorist.

They knew of course that most Muslims are not terrorists and most conservative Muslims are not terrorists, and most members of Muslim student groups are not terrorists, but they figured, well, if we're in places to intercept people at that stage, maybe we can spot them before they become terrorists. So you end up spying on a lot of people who never become terrorists in the hopes that you'll find the one.

GOLDMAN: Let's just remember something about 9/11. The people who committed 9/11 weren't born and raised in Brooklyn, they weren't from America. That's something that's been lost in this conversation.

How could a giant net of superficial information—like what was playing on TV in a Muslim-owned coffee shop, what people were talking about in barbershops frequented by Moroccans—how could that work if the goal was to deeply penetrate those communities?

APUZZO: Well it's two prongs, it's the Demographics stuff which you're talking about, the huge net of superficial information—that was the NYPD looking for "hot spots," right? If a terrorist were on the loose in New York City, we'd know where he'd hang out. We'd know where to find him. We'd know where these people gravitate to.

Then there was the informant-building and the undercover operations which were the sort of deep penetration. The Intel Division was really marbled into the fabric of the Muslim community.

Commissioner Ray Kelly is undeniably data-driven. COMPSTAT and the system of "targets" or quotas largely determine how police respond to crime. Was Intel subjected to the same sort of quota system? And how could Kelly continue to justify Intel's existence and activities if the numbers weren't there? It's gathered "zero" leads.

GOLDMAN: I don't know if there was a quota system per se in Demographics, but clearly they were out to scrape up as much information as they could about these 28 "ancestries of interest" that they were looking at. There were some programs where David Cohen himself was interested in numbers, like the Debriefing program, which is essentially a snitch factory.

People of these "ancestries of interest" who somehow found themselves in trouble, the NYPD would interview them and turn them into confidential informants. Cohen himself was obsessed about it: We need to interview more people, more people, get more information.

That's why we wrote the book, and that's why we were reporting on this, because New Yorkers didn't know that the programs that they had put in place, when it mattered most, had failed. The programs are secret. New Yorkers had no way of knowing if these programs in fact were keeping them safe.

After several years of enduring criticism for the tactic, the NYPD has finally seemed to dial back their use of stop & frisk. But in May, Commissioner Kelly said that "nothing" has changed with regard to how the NYPD Intel division conducts its business. Why do you think the City has felt the need to pivot on stop & frisk and not spying on innocent people?

APUZZO: The big difference obviously is you have a federal judge who's declared that stop & frisk is unconstitutional.

The formal response from the NYPD on stop & frisk is almost identical to the response on the Muslim surveillance programs, which is, this is legal and it's protecting you and it's important and without it the city would be more dangerous. Our point has not been to advocate that something needs to be changed or that this is an unconstitutional program, our point is to hold this up and show where we are as a society more than a decade after 9/11. Not what's illegal but what we have made legal. What we tried to show in this book is how the NYPD laid the groundwork legally to get to this place.

GOLDMAN: And few ask questions. From the City Council and their own Public Safety Commission, these people are trusted with oversight. I saw something in the Daily News about how Chris Quinn has never met Dave Cohen. Has never met Dave Cohen! The person running the Intelligence Division. The next mayor, potentially, has never met the person running this massive Intelligence Division!

How much do you think City Hall and Bloomberg knew about the scope of these surveillance efforts?

APUZZO: Our understanding is that Bloomberg gave Kelly a lot of latitude. One of the things we saw from Bloomberg was when he said, "We don't even stop to think about religion" in policing.

And these documents show not only were they thinking about religion, they were deeply interested in how people interpreted the Koran. Whether people were Sunni or Shia. If you're Sunni, where on the spectrum are you? Are you Salafist? Are you Wahhabist? They spent an incredible amount of time wanting to know how you interpreted your holy book. It wasn't a question of: Does this person advocate violence? Does this person want to harm us? It's, this person takes a fundamentalist view of Islam.

GOLDMAN: Or they were associated with a particular branch of Islam. If they were a Salafist; the NYPD was deeply interested in which mosques were Salafist moques. It would be like mapping where the Satmars or the Lubavitchers go to temple.

APUZZO: So when you hear Bloomberg say that stuff, one of the big questions for us was, well is he deeply misinformed or was he lying? And I think our understanding is Bloomberg trusts Kelly deeply, he has been in many respects an incredibly successful police commissioner. He gives him a lot of latitude and is pretty hands off when it comes to the day-to-day workings on how this stuff is carried out.

Matt Apuzzo (left) and Adam Goldman (Publicity photo)

I know you can't reveal your sources, but could you talk broadly about how you started getting this information from the NYPD and how you went about confirming it?

APUZZO: We've footnoted this book and endnoted this book extensively. There's a lot of documents in here. Most of the people who helped us with the NYPD portion of this book are current and former NYPD. They're people who we spent a lot of time with, and built a reservoir of trust with because they understood that we really just wanted to understand what happened, and how this division came to be.

On the Zazi side as you can see on the footnotes, obviously we interviewed a number of federal agents—FBI, CIA, Colorado and New York officials as well.

GOLDMAN: That's the nice thing about the book though. You can read it and you have the documents that we're going to post online, so you can look at the endnotes themselves as the spine of the book. Then we have interviews with many many people on the record. In sum, there are few anonymous sources. We had Hector [Berdecia] who ran the Demographics Unit, the Cyber Unit, and the Debriefing Unit, on the record. One of the key players in all this is on the record, and we went to great lengths to get people to go on the record.

APUZZO: We had a lot more time with the book. We met many, many more people, men and women, who because of our reporting for the AP when we started making feelers for the book, were introducing to us to people we had not met before. That opened up a lot of avenues that as AP reporters, we didn't know about at the time.

GOLDMAN: Initially when we published these documents and wrote that first big story and people provided us documents, we wrote more stories, there was a snowball effect there. We started gaining momentum and people started sending us more documents because we were willing to publish this and put this out there without fear of retribution.

There's a moment in the book when Cohen asks a detective to increase surveillance on Muslims that he believes, without evidence, are involved with Hezbollah, and the detective essentially replies, "Hey, we have a Constitution, remember?" To what degree do you think the NYPD officials or sources you spoke with kept the Constitution in mind when carrying out their work?

APUZZO: Oh, the vast majority. You have to remember, these are incredibly good people.

GOLDMAN: The NYPD detectives.

APUZZO: Yeah, these guys believe that their mission is to keep the city safe and what we tried to do in this book is show how that goal was implemented. The programs that we have here came from a place of believing that this was the way to keep the city safe.

And that's why you have people like Hector, who come back from Iraq and they really believe that this is the way to keep the city safe, and their opinion starts to change over time. I think a lot of people feel a tremendous amount of personal responsibility and pressure every day to be on the front lines keeping the city safe. But if you're told to report whatever you see, that you have to be a listening post, and these terrorists could be anywhere, and you're not really given any training about the nuances of Islam, you think, "I'd better report that I saw two Korans." Well, what does that mean?

GOLDMAN: Or, "This guy hates Jews." And by the way, let's remember something: you can hate Jews and blacks, it's not against the law. It's freedom of speech! [Laughs]

There's an interesting response to one of the NYPD's responses to the Handschu lawyers in one of their motions in court, which is all going to come to head on October 1. There's going to be oral arguments in federal court. Anyway, Cohen talks about how flag burning would be a constitutionally-protected acitivity that would cause concern!

APUZZO: Right, he essentially talks about how if you're burning a flag, that's something that would get you investigated as inciting violence. There are quotes from Larry Sanchez [Cohen's former top deputy and another ex-CIA employee] in the book where he talks about, "Hey look we have to think differently about activities that would be protected by the First and Fourth Amendments because they could actually be precursors to terrorism."

That's just an incredible thing, when you think about the fact that a municipal police department is taking it upon itself [to decide] that constitutionally-protected speech is a warning sign for terrorism.

GOLDMAN: But this is what New York created, no questions asked, when they brought David Cohen in, who used to be the deputy director—the top spy at the CIA. What does the CIA do? They gather intelligence. They don't make cases. They gather intelligence overseas. The last thing these guys want is to see is their information end up in a court of law because they'd have to reveal sources and methods.

And that's fine overseas, but that's not what we do here, people would argue, where we have a Constitution.

APUZZO: The real takeaway for us on this was, the Abdulmutallab [the "Underwear Bomber"] incident, where we allowed this guy to get on a plane. We missed real intelligence, real warning signs. How did he get through the systems we set up? There was an internal intelligence community review, Congress did a review, the press was all over it.

When Zazi slipped through the NYPD Intelligence Division's many, many, many tripwires, there was no review. Nobody went back and said, "Hey let's find out how the Demographics Unit, how did all our informants, miss Zazi?"

GOLDMAN: What about Shahzad? [the "Times Square Bomber"] I mean, he was—that bomb, for a fault in physics or a fault in the bomb, that bomb was gonna go off! What would New Yorkers have said in that bomb had gone off, or if Zazi had been successful? Would people have treated the NYPD like the federal government? Hey, we just spent hundreds of millions of dollars or a billion or whatever it is, why didn't you catch these guys?

APUZZO: Our point is just that there's not that question of, what are we getting? As a populace, what are we getting for what's been built? And what are we giving up in exchange?

And now we know. What we're giving up in exchange is police departments have the right or believe they have the right to go to wherever Muslims are and sort of hang out and build files on people talking about political and religious speech. We try to raise that question. What are we giving up and what are we getting in return? We chose to do the book on the case that was the moment that it mattered most.

GOLDMAN: Matt and I are Washington reporters covering the NYPD. We can't do this forever. There's still more important reporting to be done on the Intelligence Division. We got just a snapshot of their activities involving Muslims. They're also involved in other activities.

In fact you look at Occupy Wall Street, that movement, the NYPD was rousting guys who were in leadership positions on bench warrants. How did that happen? How did they get those names of those guys, right? There were signs that they infiltrated Occupy Wall Street and you have to ask yourself, what's the justification? So there's a lot more reporting to be done out there.

There's an analogy in the book about the fire hose of information that the authorities have to sift through when investigating terror cases. Rules limiting the collection of that information protect us from constitutional violations, but don't rules also serve the practical purpose of limiting that flow of information and make it more actionable and manageable in the first place?

APUZZO: Sure, I think the Zazi case, for all its problems, I think it shows that you can follow the rules. You can follow the rules of interrogation, you can follow the rules of using criminal courts, you can follow the rules of FISA, and you don't need to sort of throw out old rules to get this done.

GOLDMAN: Though in the Handschu case, the judge lowered the standard to "a reasonable indication." I mean really, what is that? A "reasonable indication" is really a non-standard standard. You could walk outside and go to a place where there had been crime in the past and look at one of these buildings and say there's a reasonable indication that there's a crime being committed in one of those apartments right now.

APUZZO: And some of the standards are not just reasonable indication, but "a possibility of." I mean, where is there not "a possibility of crime"?

GOLDMAN: Yeah and before that there had to be a specific evidence that a crime had been committed. The question is, if you raise that standard and the NYPD has to follow it, would that force them to be more efficient?

Do you have a sense of how your reporting has been received in the department? Ray Kelly said that your book has "a fair amount of fiction."

APUZZO: Not really. Ray Kelly has made his views clear, and that's fine. We hope that this is a vibrant discussion. We're talking about how to keep our biggest city safe, and the best way to protect the city, and to protect constitutional rights. What could be bigger issues than that? We want people to talk about this. That's what free and spirited debate is all about, and that's only good for the police department and for New York City.

GOLDMAN: I hope our book stimulates more conversation in the New York media, and editors say, "Let's keep at this." That's what reporters do. We try to ask questions and hold institutions and bureaucracies accountable.

Apuzzo and Goldman will be at Book Court tonight, the Bookmark Shoppe tomorrow night, and at the Brennan Center for Justice on September 16 to discuss their book. This interview has been edited and condensed.