– The Lebedev Physics Institute in Moscow helped the Soviet Union detonate its first nuclear bomb, figured out how to build a hydrogen bomb and has stood for decades in the vanguard of Russian scientific achievement. Seven of its scientists have won Nobel Prizes.

So it came as a shock last week when, shortly before celebrations to mark the 85th anniversary of the illustrious institute’s founding, its halls were suddenly swarming with security officers wearing masks and armed with automatic weapons.

They searched the office of the institute’s director, Nikolai Kolachevsky, and questioned him for six hours about a supposed plot to export military-use glass windows. He later denounced the raid as a “masked show,” a phrase Russians use to describe increasingly over-the-top interventions by law enforcement agencies.

The operation set off another round of what in recent months has become a favorite, if depressing, parlor game for Russia’s intelligentsia: trying to figure out why “siloviki,” or “people of force” — security, intelligence and military officials — have been acting so strangely and in ways at odds with the stated policy goals of President Vladimir Putin.

It also provided a grim example of why, despite its scientific prowess, Russia has had such trouble diversifying its economy beyond just pulling oil, gas and other resources out of the ground. Putin has for years called on scientists to look beyond their books and laboratories and use their world-class talents to help build a modern economy.

But those who try to do so run a serious risk of getting raided by masked men with guns. Cases tend to drag on for months or years, leaving the careers and nerves of suspects shredded, even if they are eventually exonerated.

That happened to Dmitri Trubitsyn, a former physicist who was arrested in 2017 in connection with a successful high-tech company he had set up in Siberia with fellow scientists. The case was finally closed more than a year later because of a lack of evidence to support accusations that he was running a criminal conspiracy to deceive regulators.

Meeting with security force commanders Wednesday in the Kremlin, Putin praised the Federal Security Service — known as the FSB, the successor to the domestic arm of the Soviet-era KGB — for its growing role in “Russia’s integrated security,” while conceding that law enforcement agencies needed to work on “strengthening public confidence in them.”

When they descended on the Lebedev Physics Institute last week, the security services carried out simultaneous raids on scientists and their family members. The main target of their investigation seems to have been Olga Kanorskaya, daughter of a Lebedev scientist and owner of a private company that, from an office she rented at the institute, built up a small business selling precision glassware.

The intimidating scale of the investigation, with dozens of armed officers mobilized for the raids, “is brazen, stupid and very frightening,” Kanorskaya, 36, said in an interview.

Security officers stormed her apartment just as she was sitting down for her morning coffee, while another team searched her parents’ apartment. They rifled through her possessions in search of evidence to prove an accusation that she says is “totally fictitious” — that she tried to export pieces of glass with potential military applications to Germany, a crime that carries a sentence of seven to 20 years in prison.

She was taken in for questioning by police investigators and an FSB officer.

No matter what the outcome of the investigation, the Lebedev institute’s scientific council complained in a tart statement that last week’s raids had “delivered colossal reputational damage with law enforcement organs discrediting themselves in the eyes of the scientific community.”

Noting that the Kremlin had announced a special program last year to make scientific research more attractive and rewarding, particularly for young talent that might otherwise emigrate, the council added that the actions of Russia’s security forces “are impossible to imagine in a civilized country in which law enforcement agencies concern themselves with real, not invented, problems.”

As with other examples of an increasingly aggressive and erratic security apparatus — the planting of drugs on an investigative journalist, the jailing of pacifist religious believers as “extremists” and other laughably fanciful cases — the physics institute saga has generated a swarm of theories to try to explain what is going on.

One popular explanation is that the case is related to coming elections at the Russian Academy of Sciences and a bitter rivalry between the Lebedev Physics Institute and the Kurchatov Institute, a nuclear research center. Kurchatov is headed by Mikhail Kovalchuk, whose brother, Yuri Kovalchuk, is a banker in St. Petersburg and an old friend and crony of Putin.

Mikhail Kovalchuk and the Lebedev Institute director, Kolachevsky, are both candidates in the Academy of Sciences elections. The two scientists have also clashed in the past over plans by the Kurchatov Institute to commercialize its nuclear projects.

Referring to the elections in a message sent to fellow physicists after the raid on his office, Kolachevsky said, “I did not want to link these two events — but the scientific community itself has already come to a conclusion.”

The case centers on the activities of Trioptics, a company Kanorskaya set up in 2016 in partnership with a subsidiary of Rusnano, a state-owned venture that promotes the development of high-tech enterprises. Kanorskaya later split from the state-funded company, buying out its 35% share in Trioptics and moving in 2018 into office space rented from the Lebedev Institute.

“There is nothing secret or sensitive in what we do,” she said, explaining that her business involved buying specialty glass from China, processing it in Moscow and then selling it for use in meteorological stations and other precision equipment, often to foreign clients.

Neither Kanorskaya, her father, nor Kolachevsky has been formally charged.

Kolachevsky, in his statement to fellow scientists, noted that the raid on his institute was the first time that a research center connected with so many renowned scientists had been “turned upside down by the ‘polite people,’ ” — Russian slang for security service thugs.