The American soldier, Gordon Black, seemed smitten with the Russian woman he met while stationed until last month in South Korea. She poked fun at him, called him her “husband,” prompted him to swear in Russian. Then, last fall, she returned to the Far Eastern Russian city of Vladivostok without him.

The woman, Alexandra Vashchuk, even photoshopped him out of a picture with her.

But when the lovestruck 34-year-old Army staff sergeant followed her to Russia — without notifying his commanders or getting permission — he landed in jail. He is charged with stealing from her, was ordered held until July 2 and faces up to five years in prison.

Black, 34, is married but going through a divorce, family members told The Washington Post. He was supposed to be on leave, returning to Fort Cavazos in Texas. Instead, he traveled to Vladivostok last month to see his girlfriend, they said.

Russian media reported that he flew there last month. The State Department has warned Americans against traveling to Russia, and the Pentagon has barred military personnel from traveling to the country.

Details of Black’s murky love affair with Vashchuk, 31, were uncovered by Radio Free Europe/Radio Liberty journalist Mark Krutov, who traced her TikTok account, which has since been made private.

In one video, the staff sergeant stands in his uniform looking at Vashchuk with doe-eyed incomprehension as she speaks in Russian, using a derogatory term for an American. “I came home, and there was this pindos,” she said. “That’s funny. Who are you? Who are you, man?”

Black takes a step, leans over and smooches her phone screen.

“Oh God! Also funny, this chevron right here,” she says, touching the military patch on his shoulder. “It says KATUSA. You’re not a saboteur by chance?”

The Korean Augmentation to the United States Army (KATUSA) is a training academy of the 8th Army in South Korea.

On Friday, Black faced the Pervomaisky district court in Vladivostok, charged with “theft causing significant damage.” He was ordered jailed until at least July 2, pending trial.

Russian courts often prolong pretrial detention periods. For example, American journalist Evan Gershkovich of the Wall Street Journal, who was arrested while on assignment in the Urals city of Yekaterinburg last year and charged with spying, has been jailed in Lefortovo high-security prison for more than a year. Gershkovich, his employer and U.S. officials vehemently deny the charges against him. But Russian courts have repeatedly prolonged his detention and denied his appeals to be released.

Black’s arrest potentially complicates difficult back-channel negotiations between Washington and Moscow over the release of Americans held by Russia. Western officials have cited a growing Russian practice of hostage diplomacy — imprisoning Americans as bargaining chips to be used in prisoner exchanges.

Among those Americans currently imprisoned in Russia are Paul Whelan, a security consultant arrested in 2018 and serving a 16-year prison term on espionage charges that he says were trumped up; Alsu Kurmasheva, a journalist with RFE/RL who was arrested last year while visiting relatives and charged with failing to declare herself as a foreign agent; Marc Fogel, a schoolteacher convicted in 2022 and sentenced to 14 years for possession of medical marijuana; Ksenia Khavana, a beautician arrested during a trip to Russia to visit family in February, who was accused of donating funds to Ukraine; and Travis Leake, a teacher and musician, arrested last year on drug charges.

The relationship vibe between Black and his Russian paramour seemed odd, according to social media videos. In one — which she captioned, “How does your husband assess relations between Russia and America?” — he gave a rambling answer critical of the United States, President Biden and NATO, parroting Kremlin talking points justifying Russia’s invasion of Ukraine.

“The relationship definitely isn’t good now,” Black said, referring to the United States and Russia. “It was definitely better under Trump.”

“America, I think, NATO is pretty aggressive, honestly,” he added. “I understand Russia’s position, obviously. They want to defend their country, you know.”

Moscow contends, falsely, that its February 2022 invasion was a response to Western aggression, complaining that Washington is using Ukraine as a proxy to dismember Russia.

President Vladimir Putin has demanded that Western leaders accept Russia’s illegal claim to have annexed a large portion of southeastern Ukraine and that they stop providing military assistance to Ukraine, which would pave the way for Russia to dominate the country.

Russia’s demand for an end to Western weapons supplies to Ukraine resonates among many in former president Donald Trump’s MAGA faction of the Republican Party, as well as in far-right and far-left political circles. Some argue that Ukraine must surrender land in return for peace, a position that is deeply unpopular in Ukraine itself.

In the video, Vashchuk asserted that Trump is better than Biden, and Black did not disagree, responding that “Biden, he’s, he doesn’t handle situations the way he should, and I think that’s one of the bigger reasons things are the way they are now, and it’s not just with Russia. Like, you can see it with other countries, too.”

Vashchuk criticized NATO as “an aggressive structure” and said that Black “understands Russia’s position; he understands Putin’s position.” She asserted that her circle of Russians, Americans and Europeans all believe in Putin’s position.

One of the videos depicts Vashchuk alone, walking along a South Korean street a stone’s throw from an American military base in Pyeongtaek in rural South Korea, about 37 miles south of the capital, Seoul.

“And this is, let’s say, an American street for relaxation. We call it drunken street,” she said, gesturing toward U.S. Camp Humphreys, America’s largest overseas military base. “Just over there, behind the gates.”

According to RFE/RL, Vashchuk said on TikTok that she had lived in South Korea for five years.

Other videos depict visits to nightclubs and bars, showing people dancing, drinking and what appear to be two Americans in civilian clothing passed out in one bar amid blaring music and disco lights.

According to Russian investigative outlet Agentstvo, Vashchuk reported Black to police for allegedly beating her and stealing 200,000 rubles (about $2,174). Agentstvo said she had made several reports to police in the past, accusing her mother of violence and of threatening violence on another occasion, as well as reporting a man who was living in her house for allegedly driving his car into another vehicle.

Missy Ryan and Alex Horton in Washington and Natalia Abbakumova in Riga, Latvia, contributed to this report.