WASHINGTON – To the neighbourhood gossips, the grand grey Russian building atop the hill was a goldmine.

Now it’s empty.

Amid escalating tensions, the U.S. government this month kicked Russians out of three diplomatic buildings, one of them an international-trade annex perched majestically atop a slope in Washington.

Neighbours watched the exodus from the surrounding balconies. The Russians hauled out trash bags, and had one last barbecue behind the beaux-arts mansion. Only this time it wasn’t steak they were charring, but documents.

The neighbours had often swapped stories that caused some to suspect they were living at the epicentre of a real-life spy-versus-spy showdown — a true, bricks-and-mortar version of the fictional rezidentura from TV’s Soviet espionage drama, “The Americans.”

“I know that building well,” said David Major, a retired senior FBI executive, ex-counter-intelligence official, and now head of the C.I. Centre, which provides counter-intelligence training.

“There’s a lot of little activities in Washington — what I call the hidden Washington that nobody knows. But if you’re in the spy business you know these little nooks and crannies.”

He wondered whether there are still little wooden boxes up on its roof. There aren’t, he’s told. Well, he explained, there used to be some equipment for the Russians to communicate with satellites: “We have pictures of it.”

Neighbours noticed a spike in other activities recently as international hostilities mounted.

Cars started filling the parking lot at night. State-of-the-art surveillance cameras appeared above the street. Wi-Fi and cellphone signals started dropping — but only in rooms facing west, toward the Russian building.

Then there was that burglar with no bag. On a January night, a neighbour spotted the hoodie-clad intruder on a fire escape.

“He just sort of caught my eye,” said the neighbour, who spoke on condition of anonymity for fear of recriminations.

“I’m like, ‘Wait, that looks like a guy up there… It actually is a guy.'”

He shouted for the trespasser to leave. In a thick eastern European accent, the man replied that he’d climbed up there to hide from an assailant. Then, in a flash, he was gone.

A snippet of what happened was captured on security video from next door. The man jumped off the fire escape onto the narrow top of a wooden fence, then pulled himself over another fence into an adjoining parking lot. Footage shows him sprinting through the nearby lot, tucking something into his hoodie.

“He was pretty spry,” said the neighbour.

Mark Stout, an ex-CIA Russia analyst and former intelligence officer, suggested the possibility that the man had been tending to eavesdropping gear.

“He could have been doing something as simple as planting a battery,” Stout said. “That is an obvious place to surveil the Russians — and the Russians would be extremely interested in that.”

Stout said he supports the U.S. government’s decision to close the buildings. He said the U.S. had no choice but to respond after the Russians ordered the U.S. to slash hundreds of staff in Moscow, following the U.S. expulsion of several dozen Russians.

It’s far from the first such tit-for-tat dispute.

Major described it as the third round of U.S.-Russia diplomat-tossing since the tail end of the Cold War — the others were in 1986 and 2001. He also floated some theories about the odd things witnessed by neighbours.

An unusual number of cars in the parking lot? “Pre-positioning,” Major suggests: intelligence officers using a quiet, discreet spot with easy access to set their vehicles up before embarking on clandestine meetings.

Then there’s the intermittent interruptions in wireless service.

In the late-Victorian townhouses next door, neighbours used different internet and cellphone providers, but all had similar complaints about poor signals on the western side.

Phone calls, videos, Bluetooth headphones — all would snap, crackle and pop in the rooms that faced the Russians.

One neighbour says his internet access was twice as fast after the Russians left. Another noticed no difference.

Added a third: “I think it’s a net positive they’re leaving.”

Now the vacant property is guarded by American federal police. Linger too long in front at night, and they’ll shine a flashlight in your face.

So what went on here? Major said he’s certain the building offered cover for Russian espionage activity.

“(It’s) not likely — (it’s) for sure,” he said. “It’s been used for a base of human operations.”

The Russians spread this activity spread around their different properties, to make it harder and costlier for the U.S. to monitor comings and goings.

As for whether the neighbours were living at the nexus of another chapter in the Russian-American spy war? Not so much, he said.

“No, no, no — (they’re) not the epicentre of anything,” he said. “It’s just another place in Washington (which) they use as a base for human operations.”

The real ‘rezidentura’ — the true hotbed of U.S.-Russia spy games, said Major — is in a bigger building, on a taller hill, just north of Georgetown: the Russian embassy.