05/22/2012 -In a letter found in hisAbottabad compound, former al Qaeda leader Osama bin Laden said the kill or capture of senior members was the result of operational security (OPSEC) failures that could have been avoided. Bin Laden recognized that practicing good OPSEC made operations slower, but saw it as a necessary trade-off for secure communication.

“Reality has proven that American technology and its sophisticated systems cannot arrest a mujahid if he does not commit a security error,” he said in a message composed sometime between 2010 and 2011.

The Combating Terrorism Center at West Point recently released 197 pages (175 pages translated from Arabic) of documents found by Navy SEALs in bin Laden’s Abbottabad, Pakistan compound. The documents included letters from bin Laden discussing al Qaeda OPSEC strategies.

As a precaution, bin Laden avoided using the phone and e-mail. His million-dollar Abbottabad compound had no phone or internet connection. All of his communication went through letters hand-carried by couriers on electronic storage devices.

Upon delivery, the messages were saved on an empty storage device -- if the device was intercepted by an intelligence agency, agents would only gain access to the single message. Using courier exchanges, it would take at least a week to send amessage and receive a response, the CTC estimated.

Bin Laden was particularly concerned about U.S. aerial surveillance capabilities, recommending against meeting hostage negotiators in areas within range of U.S. surveillance.

From the CTC:

Bin Ladin devised what may be termed as the “art of clandestine courier delivery.” It started with Bin Ladin saving his letters or media statements on some sort of electronic storage device (such as a thumb drive or a memory card) before handing it to his courier who picked it up from his residence. His courier would then meet the courier of the intended recipient in a tunnel or at a “roofed section of a market,” preferably on an overcast day to avoid U.S. surveillance. The electronic media would then be handed to the recipient’s courier who would, in turn, hand carry the message/electronic device to the intended recipient.

Bin Ladin provided clear guidance that each leader should not have more than one or two couriers and that each courier should meet with his counterpart no more than twice a week. To minimize the likelihood of someone providing the locations to the United States or its allies, Bin Ladin stated that leaders “should know the locations of the brothers, but they should not know your locations, except for the carriers” and that this applied to “every amir.” Finally, it was not uncommon for the recipient to be directed to delete the message after reading it.

Bin laden also worried about tracking devices embedded in common items. For al Qaeda members traveling he advised ditching items they had prior to the trip, luggage included, “because it might have a chip.”

He was "clearly OPSEC savvy or he would not have evaded the United States for close to a decade after the 9-11 attacks. His letters provide some insight into the range of considerations and calculations he made,” said the CTC in the most recent issue of its newsletter, theCTC Sentinel.

The irony of bin Laden’s strict OPSEC requirements: It was ultimatelyaerial surveillance and his courier’s movements to and from his compound that would reveal his location, leading to the U.S. raid where he was killed by Navy SEALs.

“The Americans have great accumulative experience in photography due to the fact that they have been doing it in the area for so many years. They can distinguish between houses frequented by men at a higher rate than usual,” he warned in one letter.