Behind him, he saw a man picking up an umbrella.
That umbrella, they thought, was not a normal umbrella, but one that had been transformed into a gun.
Umbrella guns are by no means the only type of disguised weapon.
In 1978, Georgi Markov was on his way to work at the BBC in London when he felt a sharp sting on his thigh. Behind him, he saw a man picking up an umbrella. The man, who spoke with a foreign accent, apologized and hurried into a cab that whisked him away. That night Markov came down with a fever; four days later he was dead from ricin poisoning. A medical examiner found a tiny pellet, less than 2 millimeters in diameter, in his leg. Markov, a dissident novelist who had defected from Bulgaria,…