TIMBUKTU, Mali -- The convoy of cars bearing the black Al-Qaida flag came at high speed, and the manager of the modest grocery store thought he was about to get robbed.

Mohamed Djitteye rushed to lock his till and cowered behind the counter. He was dumbfounded when instead, the Al-Qaida commander gently opened the grocery’s glass door and asked for a pot of mustard. Then he asked for a receipt.

Confused and scared, Djitteye didn’t understand. So the jihadist repeated his request.

This transaction in northern Mali shows what might seem an unusual preoccupation for a terror group: Al-Qaida is obsessed with documenting the most minute expenses.

In more than 100 receipts left in a building occupied by Al-Qaida in the Islamic Maghreb in Timbuktu earlier this year, the extremists assiduously tracked their cash flow, recording purchases as small as a single light bulb. The often tiny amounts were carefully written out in pencil and colored pen on scraps of paper and Post-it notes: The equivalent of $1.80 for a bar of soap; $8 for a packet of macaroni.

The accounting system on display in the documents found by the Associated Press is a mirror image of what researchers have discovered in other parts of the world where Al-Qaida operates, including Afghanistan, Somalia and Iraq. The terror group’s documents also include corporate workshop schedules, salary spreadsheets, philanthropy budgets, job applications, public relations advice and letters from the equivalent of a human resources division.

Taken together, the evidence suggests that far from being a fly-by-night, fragmented terror organization, Al-Qaida is attempting to behave like a multinational corporation, with what amounts to a companywide financial policy across its different chapters.

“They have to have bookkeeping techniques because of the nature of the business they are in,” said Brookings Institution fellow William McCants, a former adviser to the U.S. State Department’s Office of the Coordinator for Counterterrorism. “They have so few ways to keep control of their operatives, to rein them in and make them do what they are supposed to do. They have to run it like a business.”

The picture that emerges from what is one of the largest stashes of Al-Qaida documents to be made public shows a rigid bureaucracy, replete with a chief executive, a board of directors and departments such as human resources and public relations. Experts say that each branch of the terror group replicates the same corporate structure, and that this strict blueprint has helped Al-Qaida not just to endure but also to spread.

Al-Qaida’s grocery list

Among the most revealing documents are the receipts, which offer a granular view of how Al-Qaida’s fighters lived as well as its larger priorities.

“For the smallest thing, they wanted a receipt,” said 31-year-old Djitteye, who runs the Idy Market on the sand-carpeted main boulevard in Timbuktu. “Even for a tin of Nescafe.”

An inordinate number of receipts are for groceries, suggesting a diet of macaroni with meat and tomato sauce, as well as large quantities of powdered milk.

They list a broom for $3 and bleach for $3.30. These petty amounts are logged with the same care as the $5,400 advance they gave to one commander, or the $330 they spent to buy 3,300 rounds of ammunition.

Keeping close track of expenses is part of Al-Qaida’s DNA, said experts, including FBI agents who were assigned to track the terror group in the years just after its founding.

This habit, they said, can be traced back more than three decades to when a young Osama bin Laden entered King Abdul Aziz University in Saudi Arabia in 1976 to study economics, and went on to run part of his millionaire father’s construction company.

Bin Laden was obsessed with enforcing corporate management techniques on his employees, according to Al-Qaida expert Lawrence Wright. Workers had to submit forms in triplicate for even the smallest purchases — the same requirement bin Laden later imposed on the first Al-Qaida recruits, he said.

In Afghanistan, accounting records found in an abandoned Al-Qaida camp in 2001 included salary lists, stringent documentation on each fighter, job application forms asking for level of education and language skills, and notebook after notebook of expenses. In Iraq, U.S. forces recovered entire Excel spreadsheets, detailing salaries for Al-Qaida fighters.

“People think that this is done on the back of an envelope. It isn’t,” said Dan Coleman, a former FBI special agent who was in charge of the bin Laden case file from 1996 to 2004.

One of the first raids on an Al-Qaida safe house was led by Coleman in 1997. Among the dozens of invoices he found inside the operative’s home in Kenya were stacks of gas station receipts, going back eight years.

Terrorist expense reports

The majority of the invoices found on a cement floor in a building in Timbuktu were scribbled by hand, on Post-it notes, on lined math paper or on the backs of envelopes.

Others were typed in what may serve as formal expense reports. Al-Qaida clearly required such expense reports — in a letter from the stash, middle managers chided a terrorist for not handing his in on time.

In informal open-air markets such as those of Timbuktu, vendors didn’t have receipts to hand out. So, traders said, members of Al-Qaida came in pairs, one to negotiate the sale, and the other to record prices on a notepad.

The fighters would ask for a price, and then write it down, said pharmacist Ibrahim Djitteye.

“It surprised me at first,” he said. “But I came to the conclusion that they are here for a very specific mission … And when you are on assignment, you need to give a report.”

The corporate nature of the organization was also on display in the types of activities they funded.

For example, two receipts, for $4,000 and $6,800, were listed as funds for “workshops,” another idea borrowed from business. A flier confirmed that Al-Qaida held the equivalent of corporate training retreats.

Al-Qaida’s accounting practices left a strong impression on at least one person in Timbuktu: Djitteye, the convenience store manager.

The Al-Qaida commander who came in for mustard was Nabil Alqama, the head of Al-Qaida in the Islamic Maghreb’s “Southern Command.” One day, he asked the store employee to get a receipt book printed so he could provide more official-looking invoices.

Djitteye obliged.

The green receipt book now sits under his cash register. These days, when customers come in, he always asks if they would like a receipt.

No one ever does.