Sam—and let’s just call him Sam—is an American journalist. Last fall, he arrived in Moscow, wide-eyed and overwhelmed by the city’s tantric energy. He moved into his new apartment complex, which houses various Western press outlets and is owned, like all such buildings, by the UPDK, the branch of the Russian foreign ministry that oversees diplomatic housing.

Soon after his arrival, Sam was sitting in a Moscow café when he realized that his briefcase, which had been sitting on the floor between his feet, the shoulder strap wrapped around his ankle, was gone. He panicked. That briefcase had his iPod, his press badge, his digital recorder, and some Russian homework.

One evening, a British friend of mine, a journalist, came home to her new apartment to find a gun lying on the floor outside her door, carefully aimed at her apartment.

The next day, he received a call from a friendly woman who said her father had found Sam’s briefcase and would Sam mind picking it up? With chocolates and flowers in hand, Sam met the man, and got his briefcase back, but his iPod and recorder were missing.

He thought nothing of it, until he had dinner later with an American diplomat who was not surprised by his story. “Oh, yeah,” the diplomat said, in Sam’s recounting, “It’s your turn. That’s the FSB”—the security service that succeeded the KGB. “They do that to new diplomats and new journalists when they first get to Moscow. They just want to let you know they’re around.” And that’s when Sam realized that something had been a bit weird: The man had called Sam’s landline, which was not listed on any document in the briefcase.

There are lots of strange stories like Sam’s floating around Western diplomatic and journalistic circles in Moscow, and the recent flameup over Anna “Bond Girl” Chapman made me think of them; how Russians spy on Westerners, not abroad, but at home. It is not unusual to come home to find the furniture subtly—but noticeably—rearranged. Sometimes, a piece of furniture is missing, but reappears hours later. Sometimes, the diplomat or journalist comes home to find the computer turned on, with files and email opened. Or teams of dubious tech specialists arrive, unannounced, to fix unbroken wiring.

One evening, a British friend of mine, a journalist, came home to her new apartment to find a gun lying on the floor outside her door, carefully aimed at her apartment. Terrified, and not wanting to add her own fingerprints, she left it untouched in the hallway. When she left for work the following morning, the gun was gone.

• Full coverage of the Russian spy ringWhen another British journalist, who had just arrived in Moscow, began publishing stories on subjects unpopular with the government, such as how much money Putin had stashed away, things started to get a little weird. His children’s toys were rearranged, their windows were opened. Alarm clocks went off at ungodly hours. He wondered if he was just being paranoid. But when the British ambassador got involved and lodged an official complaint, the antics suddenly stopped. (When I called the journalist, he told me: “I just can’t be on this line. It just sort of encourages them.”)

Why rearrange furniture? Why leave windows open and ostentatiously read email? It seems that the point is to make you paranoid, upset your balance, and, most importantly, remind you that you are a guest of the Russian state. The gun in the hallway is a message, pointing in one direction: Your welcome can be repealed at any moment, just like that. Another Western journalist friend of mine is convinced that Russian agents broke into his apartment after he wrote an article the FSB didn’t like. His passport disappeared just before a planned trip to a restive region in southern Russia, and he was forced to call off his travels. Days later, he found the passport—in plain sight, sticking out between books on his bookshelf. Had he misplaced it? Perhaps. Had the agents actually broken into his apartment, taken the passport, and then returned it in an odd and highly visible spot? Also possible.

Given the recent thaw in Russian-American relations, things do seem to have cooled a bit. And the U.S. government is at pains to downplay any espionage incidents, if they speak of them at all. “My impression is that there is not as much of that as there was before,” says an embassy spokesman. “But historically this is a matter on which we push the mute button. It’s tradition. We don’t want to let them know it bothers us.”

And though we journalists can be a little self-important, we are not the only ones under surveillance. One American businessman I spoke to decided he wanted to sell the dining room table in a new UPDK building he had just moved into. When he started to take it apart, he found a microphone the size of a pencil eraser drilled into its framework. Diplomats, too, live in UPDK buildings but sometimes the agents’ methods are much more extreme.

Last year, a video of Kyle Hatcher, who worked in the U.S. embassy as the liaison to a Russian religious and human-rights group, popped up online. It seemed to have come from the FSB, though no one could definitively prove it. On the tape, Hatcher was seen making phone calls, apparently to Russian prostitutes, checking a hotel room for bugs and, it seemed, having sex with a hooker. The tape, however, was shoddily shot and spliced together, and the American ambassador complained that the whole thing was a smear.

But perhaps the most troubling detail of the Hatcher campaign was that someone had collected these video materials before Hatcher even began to work for the American embassy.

What this suggests, of course, is that someone in Russia is playing a longer game, gathering incriminating details on anyone of potential interest, hoarding these nuggets of weakness (be they related to money or drugs or sex) only to use them years later when the target has gained strategic importance.

Spy games infect people with paranoia for a simple reason: you never know when someone is watching.

Julia Ioffe is a journalist living in Moscow. She has written for Foreign Policy, The New Yorker, The New Republic, and Bloomberg BusinessWeek. Read her blog, The Moscow Diaries at True/Slant.