How to set up and use a dead-letter box...
This article describes how deep-cover agents pass messages, documents, money,
weapons, and other material between each other without compromising their
security. Neither agent knows the identity of the other. Nor do the authorities
know what's going on.
The method described in this article has been used by foreign intelligence
agencies and underground groups to thwart the counterintelligence and
counterespionage sections of the FBI.
What is a DLB? DLB is an acronym for dead-letter box. It is also called a dead
drop. A DLB is a physical location where material is covertly placed for another
person to collect without direct contact between the parties.
Good locations for dead-letter boxes are nooks and crannies in public buildings,
niches in brick walls, in and around public trash receptacles, in and around
trees and shrubs, a third-party's mail box, between books in a public library,
inside the paper towel dispenser of restaurant washrooms, and so on. The key to
success is ingenuity. If the item being passed can be disguised as a discarded
candy wrapper or hidden inside a cigarette butt, etc., so much the better.
DLB Protocol. The method described in this article was originally devised and
perfected by the KGB for use in Britain and the USA during the cold war. But the
technique is so effective it's still in use today and is used by more than 30
intelligence agencies and underground groups worldwide.
When used by two people who have basic skills in countersurveillance, this
method will confound an FBI surveillance team as demonstrated by the FBI's inept
handling of the cases involving Aldrich Ames, Jonathan Pollard, and John Walker
Tradecraft. You need to know three pieces of tradecraft to make this technique
Trick #1 Pick a good site for your DLB. This means choosing a spot where you're
momentarily hidden from view while you pass by (and either load or empty the
box). It also means selecting a site that is easily accessible and in a public
Trick #2 Use a separate set of sites to signal to your opposite number that
you're ready to place something in the DLB, or retrieve something from the DLB.
Trick #3 Use a foolproof signal that tells both parties that the material in the
site has been picked up. This guarantees that the first agent can go back and
recover the items if the second agent is unable to make the pickup for some
HINT: Be sure to use a ready-to-fill signal that can be easily seen by a lot of
Step 1: The ready-to-fill signal...
Let's suppose that you need to deliver a document to your contact. The first
thing you do is transmit a "ready-to-fill" signal. You need to tell your contact
that you're ready to fill the DLB with your material.
For example, you might place a piece of chewing gum on a lamp post at a
pre-arranged location at a pre-arranged time (perhaps the second Tuesday of each
month at 1:30 pm).
The trick is in using signals that can be easily seen by a lot of people. This
means that your contact does not have to compromise his/her security while
reading your signal.
HINT: Don't fill the DLB until you see the ready-to-pickup acknowledgement.
Step 2: The ready-to-pickup signal...
When your contact sees the ready-to-fill signal, he/she will send a
ready-to-pickup signal. Again, this signal must be sent at a pre-arranged time
and location, say at 2:00 pm. It might be a chalk-mark on a traffic signpost or
back of a park bench.
When you see the ready-to-pickup acknowledgement, you must fill the DLB within
15 minutes (ie by 2:15 pm). After placing your materials in the DLB, you
immediately return and remove your ready-to-fill signal, thereby indicating to
your contact that the box is filled.
Hint: When you see the all-clear signal, you can leave the area. If you don't
see the signal, return to the DLB and remove the material.
Step 3: The all-clear signal...
Upon seeing that your ready-to-fill signal has been removed, your contact goes
to the DLB and retrieves the material that you've placed there for him/her. This
must be accomplished before a pre-arranged deadline, say 2:30 pm. Your contact
then returns and removes his/her ready-to-pickup signal, indicating that the box
has been emptied.
When you see this all-clear signal, you leave the area. However, if you don't
see the signal by a pre-arranged time, you return to the DLB and retrieve the
material in order to prevent it from falling into unauthorized hands.
This system of signals can be made even more secure by using positive
acknowledgement signals instead of simply removing existing signals, of course.
Hint: Weave a number of fake DLBs into your routine on a daily, weekly, or
Providing security for your DLB...
NOTE: The FBI does not want you to know this.
To maintain watertight security for your DLB, simply weave a number of fake
DLB locations into your routine on a daily, weekly, or monthly basis. Narrow
passageways between buildings, covered pathways in public parks, nearby
dumpsters behind restaurants... all these are ideal.
Simply make it a point to walk past these fake DLBs on a regular basis.
Remember, each DLB is located such that you'll be momentarily hidden from view
as you pass it. If you're under surveillance, the goons will go ballistic.
They'll need to place an agent at each suspected DLB at the precise moment you
If you've chosen your sites carefully, there's no other way for the goons to
monitor these locations. If you have three or four fake DLBs that you regularly
walk past, you'll soon notice the telltale pattern of strangers who just happen
to be loitering nearby at the instant you're momentarily hidden from general
view. When this happens, you've detected the presence of a surveillance team.
Suspend your covert activities until the surveillance passes.
SURVIVAL TIP: Even if you're not using DLBs, it's a good idea to walk past fake
dead-letter boxes as a part of your weekly routine. I've caught more FBI
gumshoes than I can count with this one simple countersurveillance technique. To
date the FBI trainers have been unable to develop a defense against this
particular countersurveillance maneuver and you just haven't lived until you've
seen the facial expression of an FBI spook who suddenly realizes he's been made
by the target of the surveillance operation.
-original by: spy&counterspy, reformatting by: MRF