Aaffia Khan’s email account page included, like most, a series of file folders. She had a folder for her bills, her business contacts, a draft folder for incomplete mail she planned on sending, a trash folder, junk mail, a messages sent folder, a blank folder for travel and an empty banking folder among others. The folders were only available to one who signed onto the account page, which represented and provided a broad view of her email activities, but showed nothing helpful to Brennan’s investigation.
Nick could see nothing that tied Khan directly to Bhiren. There were often discussions about al Mohammed’s website and his call to arms and jihad, but no direct contact between Aaffia and Bhiren al Mohammed. Nick had to force himself to remember that jihad was a term of art often misunderstood by the Westerners and that many Muslims were peace-loving people. Jihad really meant “struggle,” while it was often translated as a “holy war.” But there were of course frequent patent bellicose offerings he discovered in the transmissions as well:
[2.91] and slay them wherever ye find them, and drive them out of the places whence they drove you out, for persecution is worse than slaughter [of nonbelievers]… but if they desist, then lo! Allah is forgiving and merciful. And fight them until persecution is no more, and religion is for Allah.
This was all brand new to Nicky but fascinating too—a whole different way to gain converts. He slowly read and reread the messages. He looked at each email address and looked for some pattern, something that would tie this together with a mass conspiracy and lead to the scientist who would lead to Bhiren.
Brennan’s review of Khan’s cell phone records also didn’t help. The phone she used at Grand Terminus was a “throw away,” and her private cell only provided calls to businesses and a few overseas calls to family. The squad was right. How the hell was she getting instructions from Bhiren? Was the whole theory wrong? Every reliable message NSA intercepted and every CIA source in the know recounted al Mohammed’s leading role in the attempted bombing in the US and the bombing in England. Could they all be wrong? Nicky thought.
Aaffia regularly deposited money in her bank account but had no visible means of support. Nick wondered why did she even have a bank account? Nick suspected she was the beneficiary of a “hawala.” A hawala is an informal banking system popular in the Middle East. It is a system based on trust and record keeping. It involves the transfer of money without actually moving it. In its most simple form, the sender goes to a broker in a foreign city and deposits money in a password-sensitive account. The broker advises another broker in a city sometimes across the world of the deposit, often by phone or email. The recipient visits the local broker, announces the password, at which the broker delivers up the money minus a commission. Ultimately the debts are settled by the brokers at a later date. The FBI knew there were several hawala brokers in Brooklyn and in fact throughout New York City, but they just didn’t know which one Khan had likely used. She was very careful about her calls and contacts.
Khan’s pocket litter included a series of scribbled notes, some numbers, perhaps telephones, and some business cards. She had the card for a taxi company or “car service” as gypsy cabs were known throughout New York City. She had a telephone number on an ad for a Middle Eastern grocer that had been run through FBI databanks and a variety of small papers and some receipts, some of which were illegible.
****
That night when Nick pulled into the driveway, he saw a fleeting glance of Jodie hurriedly going in through the front door. As he got into the big house, he called out from the center hallway, “Joann where are you?”
“At the sink, Nicky. I’m starting supper. I just got in from my run and I’m behind schedule.”
As Nick walked into the kitchen his breath was taken away as he saw his gorgeous wife moving dishes around while wearing a pair of black low rise spandex capris and a boxy crop top. Joann knew that sexy workout clothes helped motivate the intense exercise necessary to keep her in great shape. She turned around to greet Nick, exposing her full frontal abdominal beauty. Nick studied his wife’s form for a full moment and felt the physical passion start to burn deep within him.
“Wow, you look great!”
“Hey Nick, do you think I need a belly ring?” she said with her hands on her shapely hips and a broad grin spread across her pretty face. She was only kidding, of course, but Nick wasn’t sure and at the moment didn’t care.
“How late are you running?”
“Why?”
“I need to play a quick game of checkers, and I’d hoped that you would join me.”
“What, otherwise you would play alone… I only have twenty minutes, my handsome husband, and I’m sweaty.”
“You’re sweaty? Right now you could wring out my tee shirt and put out a fire. The way my engine is running maybe we can get two games in.”
After a brief but satisfying bout of lovemaking, Nick and Joann were resting on their pillows engaged in the soft afterglow.
“Nicky, I almost missed that train, you know,” Joann said, teasing her mate.
“Babe, the locomotive almost didn’t make it into the station, if you get my drift,” Nick responded with a giggle.
“Okay, Nick let’s change the subject, shall we? So, have you read any good books lately?”
“No, but if you restrict your comments to answers only, no questions, I do have a subject I’d like to discuss with you.”
“Shoot, I can keep a secret.”
“Joann, if you had a little notebook and it was covered with handwritten numbers, would each number or set of numbers have some relevant meaning?”
“Yes, I think so. I can’t imagine writing down numbers for no purpose or just randomly.”
“What might the numbers represent?”
“Let’s see—telephones, credit card numbers, passwords, model numbers, bank accounts, addresses, serial numbers, stuff like that. Basically a string of single numbers often in a long series, pretty common I would say.”
“If you wrote down those numbers so others couldn’t readily understand them, like a computer password, how might you do that?”
“Okay, I would create a code, but a simple one that I could remember but others couldn’t decipher easily.”
“Alright, in Vietnam a cryptologist once told me that enemy battlefield codes were usually simple and often based on juxtapositions and numbers, often prime numbers added or subtracted from the clear text. Why prime numbers?”
“Nicky, prime numbers are considered the basic building block of all natural numbers. And remember one is not a prime number. The ancient Greeks didn’t consider one to be a number at all. Prime numbers are easy to remember and identify; they can only be divided by one and themselves.”
“What are the single-digit prime numbers? Two, three, five and seven?”
“Yes, that’s right, and they are easy to remember, like I said, divisible by itself and one, and in this example a single digit only. By the way, two is the only even prime number.”
“So it is a limited universe in a sense, right?”
“Yep, sort of, except of course, for the perpetuity of numbers—and as a number added to or subtracted from another number, when it is the prime two, three, five or seven, it is easy to remember as well. But I would use the smallest prime, the number two for my code, because when it is added to or subtracted from any other single digit number including one or zero, it is manageable.”
“Okay, if I add two to nine I get eleven as replacement digits, right?”
“Yes, so if the number resulting is larger than a single digit, instead you just subtract the prime number two so you get seven, you see?”
“Okay, let’s look at another example. The number one subtract two is minus one, right?”
“Yes, so you add instead. That is three: one plus two, get it?”
“So what is happening is you are either adding or subtracting the prime number two from any single digit depending on the outcome. If you add and the new number becomes two
digits, you subtract instead, and if you subtract and it is a negative number, you reverse and add, right?”
“Yes, that is right, Nick. I don’t know that much about cryptography, but I do know that prime numbers and substitution have been popular throughout the ages. This is one example of a simple code, but if you don’t know what the number is—telephone, bank you know—you still haven’t figured out the puzzle. So even if a cryptographer in the NSA broke it, it still remains encrypted in a sense.”
“So basically a simple code is addition, subtraction and the use of a prime number, in its simplest form the number two, right?”
“Yeah, and remember the code I created wasn’t to send a message to someone, but just protect it from peering eyes. If I wanted to create a complex password to transmit, I could make it the product of several primes, for example 2x3x5x7x11x13 = 30030—the key to my transmitted message to you if you are the receiver.”
“Ah ha, so if someone is just encrypting a string of numbers the use of a prime number adjustment table can be used to create a substituted number. But even if you break it out you still have to figure out a number for what?”
“Not only are you a great lover, but you have a mind like a steel trap, Nicky!”
****
At the next morning’s meeting with the team Nick began to understand why his colleagues were becoming discouraged and disappointed with the investigation. He began his presentation with a few questions. “Why did Khan have a bank account?”
“Probably to deal with some merchants. Cash takes care of most things, but checks sometimes are necessary. Aaffia’s landlord was an up and up guy and wanted payment by check; a naturalized citizen, he wanted nothing to do with laundered money,” Al Franks answered.
“Was she using a hawala as a source of money?” Nick asked the crowd.
“Absolutely, Nick, they are throughout the city with a high concentration near Atlantic Avenue in Brooklyn,” OS Ford offered.
“Those numbers in the pocket litter, are they telephones, accounts, or what?”
“We don’t know for sure, but some of them at least are telephone numbers. We checked them out, and either they were cleared or finally didn’t play out as phone numbers at all,” Jack Mason responded. That answer intrigued Nicky. He didn’t know why, but that probably meant that after they “scrubbed” some of the numbers—a popular expression among investigators—and they didn’t pan out, they remain as question marks. Unanswered questions are leads, or at least that’s how Nick always treated them. Did they even consider simple encryption? he wondered as he walked back to his desk.
When Brennan got back to his screen, he pulled up all those numbers again. If Aaffia was going to encrypt anything, it would probably be her important notes, and the device might be a simple battlefield code, he thought, reflecting back on his conversation with Jodie. Nick discarded the numbers that were obvious telephones and focused on the ones that were not deciphered. He went through more than thirty numbers and ran them through the FBI general database and through a search engine on the Internet—no luck.
Nick decided to run the numbers as partials. Maybe they are license plate numbers, he thought. He ran the numbers in several different configurations through the National Crime Information Center, the NCIC database, without success. One strange number in particular caught his attention: “8250 2 5675477.” The last seven digits resembled a telephone number, but the “2” didn’t fit, and there was a large space between the 8250 and the remaining series of numbers.
Brennan ran the last seven digits alone in the FBI database, the Automated Case System known as ACS, without success. Then he ran the number on the Internet. There were hundreds of hits as serial numbers, partial serial numbers, model numbers, and even telephone numbers from area codes all over the US. That doesn’t get me anywhere, he thought. It didn’t seem to be an international telephone number, but certainly could be.
Nicky tried to reason the number out. The 8250 seemed separate from the rest. He left it alone. The number 2 stood alone, and the seven digits 5675477 were very similar to perhaps a local call, but the exchange was wrong. He tried to narrow the area code to New York City.
NYC has two area codes, 718 and 212, he said to himself. He ran the numbers with each of those area codes. 212 and 718 5175477 both “returned” nothing. How about backwards? he decided. He put the numbers into the blank field, slowly reversing the last four digits only, but no luck again. When he ran the last four digits in reverse 2125177745 he still had no luck. But when he subtracted the prime number two from the whole number he got 335 as an exchange, a Manhattan exchange, and by reversing the last four digits and adjusting with the prime number two he suddenly got a hit! Holy shit, that Jodie is brilliant!
2123355523 came back to a computer store in lower Manhattan. That’s certainly a possible hit and yet a real simple device. Perhaps the two represents 212 or even the prime number used, he reasoned, but what the hell, and what the hell is 8250, he wondered. The only trick in discovering the exchange Aaffia relied on was the number “1” in the middle of 517. It had to be a three; the subtraction of the prime number two from the number one would be a negative number, therefore it required an addition. Nick decided not to use the code on the other numbers right now and called out to Kevin Cleary sitting in the cube right next to his.
“Kevin, got a minute?” Nick asked
“What’s up?”
“Kev, I think one of the unknown numbers on the pocket litter is a backward phone number with a prime number adjustment with some predicate information. You know, other numbers like the 8250, I just can’t figure out what the hell that might mean. That number 8250 may not be encrypted.”
“Where the hell did you learn this prime number shit? What does your telephone number come back to?” Cleary inquired.
“It comes back to the ‘Computer Central’ store right here downtown.”
“The only thing I can think of off the top of my head is a computer model number,” Kevin guessed.
“What I know about computers you could fit on a cocktail napkin, but does 8250 sound like a computer model number to you?” Nick said, smiling.
“I don’t know, but let’s try the search with ‘computer model 8250.’”
Brennan ran that phrase and the return showed a Dell 8250 and a follow-up check showed that indeed Computer Central, the computer center on Water Street in Manhattan, featured that machine for the last two years.
Nick looked over at Cleary with his eyes widened and said to Kevin, “You want to take a ride right now?”
The two signed out a bureau car and went to the store less than a mile from 290 Broadway. As they pulled up in front of the wide storefront in a pricey part of town, they figured that the store was a big operation and fertile ground for a preliminary investigation.
“Pardon me,” Nick asked the young male clerk passing by the big computer window displays after they entered, “do you still have the Dell 8250?”
“Yes sir, right over here. It’s our best buy, you can’t beat the deal. It has everything, including all the brand-new technology. This unit comes with a sound card. You can use what is called VoIP, voice over Internet protocol, call your friend without using a telephone or a cell phone, right from a computer. You can do everything else too—send emails, search the web, file data, you know, the whole route.”
“Help me out with that. Can I call anywhere—Europe or Asia, for example—on this machine?”
“Anywhere, and it’s a cheap call. And since it is our new peer-to-peer technology, you know, P2P they call it, it doesn’t go through an ISP. There’s no switch like a telephone; it is direct and encrypted. We give you all the gear to use it.”
“Thanks. We will be back,” Cleary said slowly while thinking about what had just happened.
****
Back in the SCIF twenty minutes later, Kevin and Nick made an appointment to meet with Jack Mason. Mason quickly invited them to his office in the SCIF.
&nb
sp; “Jack, we think this number,” Nicky said, displaying a copy of the pocket litter, “when the last four digits are reversed and adjusted turns out to be a telephone number right here in Manhattan, and this 8250 is a computer model.”
“Okay, sounds good. How does that help?”
“I think Aaffia Khan bought it—you know, the computer—and that is what she used to communicate with Bhiren. It uses a new technology a telephone via Internet which probably can’t be intercepted—it goes person to person directly, and it’s called VoIP.”
“Actually, it is not all that new,” Kevin added.
“It is to me,” Nick said with a smile.
“I have heard of it but I haven’t had any exposure to it,” Jack explained.
“Well, Jack, I’d like to subpoena the records from Computer Central and see if Khan purchased that machine from that store.”
“No problem, Nicky. I want you to talk to the lawyers upstairs and perhaps we will go with a National Security Letter, an NSL. We go for the person or persons we can tie in who bought that machine. It gets us all the information we need and it places a gag order on the merchant—it is better than a subpoena.”
“Yes sir, I’m all over it,” Nick said, now exposing a big grin.
****
The FBI legal team quickly put together the NSL and an agent served it on the computer store manager. The information collected did not show Aaffia Khan buying the exotic device, but it did show an interesting woman buying the unit about two years earlier. Those records, a follow-up revealed, indicated the purchaser actually gave Aaffia’s cell number as the primary to be used in connection with any computer problems, and amazingly a landline telephone number was also given as a backup. That number, 7184927111, came back to a Brooklyn address: 734 Dean Street in Boerum Hill, not far from the local Pakistani community centered around Atlantic Avenue. This was a big break in the case, Nick knew.
Once a Noble Endeavor Page 16