It’s far from clear that Paul Whelan, the U.S. citizen arrested in Russia last week and charged with espionage, is actually a spy. But there’s definitely something fishy about his background and activities.

Whelan, 48, a former U.S. Marine and current head of security for BorgWarner, an auto parts manufacturer, traveled to Russia multiple times since 2006, though both his current and former employers say he was not traveling on business. When he was arrested, according to his family, he was attending a friend’s wedding in Moscow. He apparently had an interest in Russian culture and had studied the language and liked traveling the country by train. Unusually for a foreigner, he had an account on Vkontakte, the Russian version of Facebook. Even more unusually, most of his contacts on the site were what the New York Times describes as “men with some sort of connection to academies run by the Russian Navy, the Defense Ministry or the Civil Aviation Authority.”

Whelan’s background is murky as well. He was court-martialed in 2006 and dishonorably discharged from the Marines in 2008 for what the Washington Post reports was an attempt “to steal more than $10,000 worth of currency from the U.S. government while deployed to Iraq in 2006 and bouncing nearly $6,000 worth of checks around the same time,” as well as several other types of fraud.

In addition to the U.S., Whelan had passports from Britain, Canada, and Ireland. Apparently, he had an ongoing competition with his sister to see who could collect the most.

Whelan has a background in law enforcement, though he has exaggerated the extent of it. In a 2013 court deposition, “he said that he had been a sheriff’s deputy in Wash­tenaw County and a police officer for the city of Chelsea” though Washtenaw County has no record of him, and in Chelsea he was actually a “part-time police officer, as well as a dispatcher, a crossing guard, and a parking officer.”

The timing of the arrest has attracted attention, coming just 15 days after Maria Butina was convicted in a U.S. court of acting as an unregistered agent of Moscow during the 2016 campaign, making her the first Russian citizen convicted in the investigation into alleged election interference. Whelan’s arrest could be an attempt to set up a swap or could simply be retaliation. Butina is viewed in Russia as a political prisoner, and one Russian lawmaker on TV last week called on authorities to “arrest an American here.”

Whelan’s activities don’t seem like those of an actual government spy—one would think he would at least travel with a less conspicuous cover story. (To be fair, the Skripal poisoning suspects—or are they misunderstood Gothic architecture lovers?—have cast some doubt on the idea that real-world secret agents always carry out their business The Americans–level op sec.) It’s certainly possible that Whelan was up to something not entirely legal on his frequent trips to Russia. It’s possible this could have involved representing himself as some sort of intelligence asset, whether or not he really was one. It’s almost certain that the Russian government will extract the maximum political value from this very strange case.