MOSCOW (AP) — When Gennady Kravtsov sent a cover letter to a Swedish company, he reasoned that, even if a job didn't come of it, he at least would know whether his engineering skills were valued outside Russia.

Instead, he found himself charged with treason and facing a possible 15 years in prison.

Kravtsov worked for Russia's GRU military intelligence agency from 1990 to 2005 as a radio engineer in satellite intelligence. For five years after he quit, he was barred from leaving Russia or taking certain security jobs because of the sensitive nature of the work. But when that period was up he sent a cover letter to a Swedish company he found online. Nothing ever came of it.

In 2013, Russian counter-intelligence officers asked Kravtsov about the contact, and last year grabbed him on the street and threw him in jail.

The Russian government increasingly has portrayed any cooperation with foreign companies or nationals as a potential security threat, a throwback to Soviet times when any interaction with foreigners aroused suspicion. The eclectic group of Russians charged with treason this year includes a mother of seven, a Sochi traffic controller, a Black Sea Fleet sailor, a Siberian police major, a Russian Orthodox Church employee, a Moscow university lecturer and a retired nuclear scientist. The variety of suspects is not in itself evidence of a harsher crackdown, but Russia is clearly widening its net on treason and hauling in the most people in years.

Nine people, including Kravtsov, were arrested in Moscow in 2014 on suspicion of treason, according to the Moscow City Court. Across Russia, 15 people were convicted of treason last year, nearly four times as many as the year before, Russian Supreme Court data show.

The stepped up campaign against suspected traitors follows a Kremlin move in 2012 to expand the definition of treason to include undefined "assistance" to a foreign government, which rights activists have warned could lead to abuse.

"If you look at it, any person who has talked to a foreigner and said something bad about the government can be sent to prison," said veteran human rights defender Lev Ponomarev.

Kravtsov's lawyer, Ivan Pavlov, has handled treason cases for 20 years, but he has never had as many clients as he has now.

"They look for enemies and they find them. These are various people, from a breastfeeding mother to former intelligence agents," Pavlov said. "The mood in law enforcement agencies, how aggressive they are, their zeal to intensify their search and prosecute (more people) stem from the developments in Ukraine and Russia's position in the world."

He said "every single treason case" he has seen recently has a connection to the crisis in Ukraine — where the government is fighting a pro-Russia insurgency — either because the person had traveled there or had some personal ties.

Russia is returning to old Cold War tactics in other ways as well. In July, the Nizhny Novgorod State University fired its vice rector, an American who had lived in Russia for two decades, after a state television program criticized him for hanging portraits of American scientists on university walls. When state media seek to discredit Russia's marginalized opposition, they often accuse them of being too cozy with Western diplomats.

It is the treason campaign that perhaps most evokes the repression of the Soviet era.

"At first I thought he was the only 'spy' in prison," said Kravtsov's wife, Alla Kravtsova. "Then I realized it was a war-time campaign. A campaign to catch spies had begun and Gena was at the right time in the right place with his stupid letter."

Pavlov is barred from discussing details of Kravtsov's case, but he said that prosecutors are accusing his client of revealing his job description at the GRU, as well as information about the military capability of the Tselina-2 radio surveillance system. Kravtsov's defense argued that since the satellite, invented in the 1970s, has not been in use since 2000, information about it should not be classified. The lawyer himself has been kept in the dark about much of the case, he said, and the defense was helpless since the government list of classified information is classified as well.

Kravtsov's case was heard at the Moscow City Court, with the trial proceeding behind closed doors. Kravtsov's wife turned up at every hearing, even though she was not allowed in. She stood outside, straining to listen through the door and waiting to get a glimpse of her husband whenever it opened.

Prosecutors on Monday asked the court to sentence the 47-year-old Kravtsov to 15 years in prison. The verdict is expected next Monday.

Kravtsov, a father of two, quit his GRU job in 2005 because he felt that the military intelligence agency was wasting money and his talent, his wife said. He got a job at a think tank in Moscow, but once the five-year ban on travel and employment in security-related jobs expired, he started exploring other options.

His wife said he sent a letter to the Swedish firm, using an online program to translate it into English, and soon got a reply that the company was not interested.

"He just wanted to find out whether his skills were in demand elsewhere or he should get new training and work somewhere else," Kravtsova said.

In 2013, he wrote one more letter, "a cry for help," as his wife described it. She said he mailed a letter addressed to the Belarusian defense minister saying he was frustrated with the decline of his field in Russia and wanted a job in Belarus, a former Soviet republic that remains a close ally of Moscow.

A few months later, in July 2013, Russian counter-intelligence officers approached him on the street.

"They came for him, showed him their ID on the street, as in Stalinist times," Kravtsova said. "They didn't even let him go home, but put him in the car and took him to their office."

She said the FSB officers asked him about the email to Sweden and seized his computer the same evening. For the next year, Kravtsov dutifully answered the investigators' calls and went to meet with them whenever they asked, although there were no charges against him. His wife said the investigators told him he was free to travel, but just after the family bought a package tour to Greece, Kravtsov was arrested on the street, his arms pinned behind his back.

The FSB, the main successor to the Soviet-era KGB, did not respond to a written request for comment.

Both of Kravtsov's children, 4-year-old Vasilisa and 8-year-old Anton, know that their father is in prison. His wife said that when Anton was asked in school why his father no longer comes to pick him up, the boy said: "He's in prison, but don't be afraid, he's a political one."

Pavlov thinks that senior Kremlin officials no longer have to send orders to their subordinates to crack down on dissent or to be on the lookout for spies, because the political system has taken on a life of its own.

"Every official on every level, from investigators to judges, they feel it; they don't need anyone to pick up the phone and call them," the lawyer said. "Everyone knows what to do."