Throughout all of human history, there has been one type of soldier whose fate is sealed the moment they're caught. Spies have always been treated differently than any other combatant, and so many of them made sure they could never be taken alive. Here's why.
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| A Spy escorted by German Police |
As Old as Civilization
Spying is as old as civilization itself. The moment humans started forming tribes and kingdoms, they figured out that knowing what the enemy is planning before they do it can be worth more than thousands of soldiers. The ancient Egyptians already had operatives called the Eyes of the Pharaoh who monitored rival powers, developed secret codes and invisible inks, and even pioneered using poisons for assassination.
But it was Sun Tzu who put it into a system. In The Art of War, written over 2,000 years ago, he argued that staying ignorant of your enemy was inhumane because it leads to longer wars that kill more people. He broke spies into five categories, including one he called doomed spies. These were agents you deliberately gave false information, fully knowing they would get caught and killed, but only after revealing your fake plans under torture. Sacrificing your own people was considered acceptable strategy.
From the very start, spies were playing a game where the rules openly accepted their deaths as part of the plan.
Why Spies Get Executed
Soldiers who fight in uniform are considered lawful combatants. If captured, they become prisoners of war with certain protections. But spies are treated completely differently. International law defines a spy as someone acting under false pretenses to gather information. The key word is disguise. A soldier in uniform who sneaks behind enemy lines is technically a scout with POW protections. But the moment you put on civilian clothes or an enemy uniform, you've crossed a line.
The reasoning is that this kind of deception is so dangerous to the entire system of warfare that it deserves the ultimate punishment. The Hague Convention required that a spy be given a trial before execution, so they couldn't just shoot you on the spot. But after that trial, execution was entirely legal.
The Second World War
When the Second World War erupted, complex technologies like radar, rockets, and atomic weapons made intelligence more valuable than ever. Britain created the Special Operations Executive to conduct sabotage across occupied Europe. The United States created the OSS. Germany had the Abwehr for military intelligence and the Gestapo for enforcement.
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| German Abwehr Unit |
Agents who parachuted into occupied Europe feared the Gestapo above everything. They were taught to stay silent during interrogation for at least 48 hours so everyone in contact with them could relocate. Some managed it. Most did not. Of roughly 470 agents sent into France, 118 never came back. Many suffered prolonged torture before being killed.
Because of this, one of the darkest inventions in espionage was created: the L-pill. L stood for lethal. A glass capsule of concentrated potassium cyanide covered in brown rubber, sewn into shirt collars or hidden in coat buttons. If an agent bit down hard, the glass broke and death followed in seconds. A quick death by your own choice was simply preferable to what awaited you in a Gestapo basement.
Even top Nazis carried them. Heinrich Himmler bit into a concealed cyanide capsule days after being captured by the British.
The Double Cross
When Germany launched its espionage campaign against Britain, agents arrived by parachute, submarine, and through neutral countries. But MI5 caught almost all of them. Once caught, they faced a simple choice: execution or betrayal.
Those who agreed to switch sides had their radio equipment set back up and began feeding disinformation to their German handlers. This became the Double Cross system. The Abwehr believed they had an extensive spy network in Britain. In reality, every single message was being written by British intelligence.
The most celebrated double agent was Juan Pujol Garcia, codenamed Garbo. He created a fictional network of 26 sub-agents who never existed, but his reports were so convincing that Germany awarded him the Iron Cross while Britain awarded him an MBE. He is one of the only people in history decorated by both sides of the same war.
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| Double Agent Garbo - Juan Pujol Garcia |
The Double Cross system proved crucial for D-Day. Double agents fed information about a phantom army at Pas-de-Calais with inflatable tanks and dummy equipment. Hitler was so convinced that he refused to reinforce Normandy for seven weeks. By the time he realized the mistake, the Allies were firmly established on the continent.
Atomic Betrayal
When the United States dropped its first atomic bomb in 1945, Stalin already knew more about it than most American politicians. Soviet agents inside the Manhattan Project had been passing technical information to Moscow for years. The Soviet Union detonated its own bomb in 1949, only four years later, built essentially as a replica using stolen specifications.
Julius and Ethel Rosenberg, who had passed atomic secrets through a network of contacts, were convicted of conspiracy to commit espionage. The judge called their crime worse than murder because it made global nuclear war possible. On June 19th, 1953, they became the first American civilians executed for espionage during peacetime.
The Cold War
Berlin became the epicenter of espionage, the only place where East and West came into direct physical contact. The CIA and MI6 dug a 1,500-foot tunnel from the American sector into East Berlin to tap Soviet military communications. For months they gathered intelligence that seemed extremely valuable. But a British MI6 officer named George Blake, who was himself a Soviet agent, had betrayed the project before it even began. The Soviets knew everything and chose to let it continue so they could feed disinformation.
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| American sector - East Berlin Tunnel |
While the West executed spies with trials and firing squads, the Soviets made brutal examples. When Colonel Oleg Penkovsky was arrested in 1962 after providing crucial intelligence during the Cuban Missile Crisis, he was interrogated roughly a hundred times before execution. Rumors circulated that he had been strapped to a stretcher and pushed alive into a crematorium while other intelligence officers were forced to watch.
In 1985, the year of the spy, CIA officer Aldrich Ames walked into the Soviet embassy in Washington and handed over the names of virtually every American spy inside the Soviet Union. He did it for $2.5 million over nine years. At least 10 of the people he betrayed were executed as a direct result.
The principles Sun Tzu laid out over 2,000 years ago remain the same. The tools have changed from invisible ink to cyber espionage. But the fate of a captured spy hasn't changed much at all.
A cyanide pill sewn into a shirt collar. That was standard equipment for agents dropped into occupied Europe, because a quick death by your own hand was the better option. Two thousand years of espionage and the one constant is this: if you get caught, the rules that protect soldiers don't protect you.
Written by Andreja Rakočević, a military history writer and co-creator of the RogerRoger YouTube channel.