MOSCOW—Paul Whelan, the former U.S. Marine imprisoned in Moscow on charges of espionage, is “under constant surveillance” in a small cell, but conditions have improved for him, his lawyer tells The Daily Beast in an exclusive interview.

At a hearing in Moscow City Court on Tuesday, Whelan appeared and looked very pale, and a little lost. He wore a light blue shirt and glasses, and appeared not to understand when the judge said his status would “remain without any changes,” meaning bail would not be allowed. His defense lawyers had to translate for him.

“We are going to appeal this decision in supreme court,” his lead attorney, Vladimir Zherebenkov, told the diplomats in the room. “He remains in custody because the investigators are still collecting evidence... There are many weak places in the investigation,” Zherebenkov said.

Whelan, 48, faces as much as 20 years in prison if convicted, but since his arrest last month there has been widespread speculation he might be traded for Maria Butina, a confessed Russian agent who sought to influence U.S. political figures through connections with the National Rifle Association.

Asked about the possibility of a trade, Zherebenkov told The Daily Beast  on Monday, “It is too early to talk about it now,” and, “I totally reject the idea that Whelan’s case is the beginning of the trade season,” an apparent allusion to what’s called the transfer window in professional sports.

Zherebenkov said Whelan now shares a cell in Moscow’s notorious Lefortovo Prison with an incarcerated Russian entrepreneur. Zherebenkov would not name the businessman. He was headed back there Tuesday. The attorney has advised Whelan that, given the Federal Security Service (FSB) surveillance, he needs to mind what he says as long as he is in jail. The former U.S. Marine staff sergeant and administrator, who was deployed twice to Iraq before being court-martialed for larceny and passing bad checks in 2008, has a passion for Russia and has made frequent visits dating back to 2006.

His family says, and his lawyer confirms, that he came to Moscow last month to attend the wedding of a Russian woman and an American friend, another former Marine, at the storied Metropol Hotel. While there, according to Russian state media, he met in his room with a man who handed him a USB memory drive containing information about personnel at a Russian security agency. The arrest, in what appears to have been a sting operation if not a complete setup, came moments later.

“When Whelan was detained, he had classified information on him, the defense insists that he was not aware that it was a state secret,” Zherebenkov told The Daily Beast.

Speaking to a gaggle of reporters after the hearing Tuesday, the attorney said, “Paul had no chance to see that classified information on the flash drive, which was passed to him by some individual. Now the investigators have to prove that he wanted that flash drive.”

The arrest took place in December, just 15 days after Butina pleaded guilty to reduced charges against her in the United States and was said to be cooperating with American investigators. Whelan’s lawyer said that he still has his job as global security director for BorgWarner, an automobile parts manufacturer based in Michigan, and should be able to keep it. In Zherebenkov’s opinion, “They cannot fire him, and they should respect the presumption of innocence.”  

With or without release on bail, the “operative investigative” activities by the FSB are going to take months, perhaps as much as a year, the attorney said. “The investigators have four of his cellphones. They need to study all his phone calls, his contacts, dozens of his Russian friends on social media, figure out who he met with—that will take a long time.” And it will also require a very alert defense to make sure whatever evidence is presented is valid.

“My job will be to find which of the records were falsified, which of the recordings were cut out and clipped together,” said Zherebenkov.

Although observers from the U.S. intelligence community think it is highly unlikely Whelan was a spy, some of his background and activities made him an easy target for the FSB if it was looking for someone to set up. Whelan, who was born in Canada to British parents, has four passports: U.S., Canadian, British, and Irish. For years, he has been friending low-ranking Russian veterans on Instagram and Vkontakte, the country’s most popular social network.

Zherebenkov told The Daily Beast he believes the FSB “must have been keeping Whelan under surveillance at least since his trip to Russia last spring,” although at that time Whelan’s itinerary was typical of a tourist. He traveled about 70 miles northeast of Moscow to the Trinity Lavra of St. Sergius, the most important monastery in the Russian Orthodox Church.

“Paul traveled to Zagorsk because he has a deep interest for Russia’s ancient culture, Orthodoxy and history,” Zherebenkov told The Daily Beast.

Zherebenkov says he likes his client’s spirit. “We spend hours talking about the law. I explain how he should answer questions. He sometimes makes jokes; the man smiles, laughs,” Zherebenkov said. But Lefortovo investigative isolation is strict: no amount of money can buy a phone call and there’s no mail, not even the kinds of messages passed by prisoners from window to window on strings.

Zherebenkov said he doesn’t like to visit prison. “Sometimes I have to lie down, completely exhausted: see, prison is a place where people have suffered for decades, it drains all the energy out of you.”

Because of Whelan’s four passports, diplomats from all four embassies have been trying to assist the prisoner, and three were in the courtroom on Tuesday.

Among other things, they have helped to set up a ruble account for Whelan in jail, so now he’s out of solitary he can buy basic things needed at the prison shop or even order food from Moscow restaurants through the prison’s administration. They are also working to get him medication for a herniated disc.

After 10 days in a single cell, wearing a blue robe under a so-called “quarantine” regime Whelan now has his personal clothes back, Zherebenkov said.

“He has a cell mate now, an entrepreneur well known in the country whose name I cannot mention here; his mate helps Whelan with translations.”

Zherebenkov also explained that Lefortovo prisoners under investigation but not in isolation are allowed to send electronic messages but, once again, only with a special permit from the prison’s administration.

Prior to the hearing,  Zherebenkov said if Whelan is released on bail he could be moved to a hotel. “That is not a problem,” he said confidently.

In a career that spans almost 40 years, first as a criminal investigator for the police, then as a private attorney, Zherebenkov is well versed about the ins and outs of high-profile prosecutions. He told The Daily Beast he has defended dozens of judges, mafia bosses, FSB officers, prosecutors, Interior Ministry officers and even bureaucrats of the Kremlin administration.

“I have more than a hundred high profile cases in my collection, including four senior criminal authorities,” Zherebenkov said. Today Zherebenkov’s legal firm employs 60 attorneys in the center of Moscow.

“My specialty is state officials, I often defend judges, prosecutors, investigators.”

Given the way the system works, he knows anybody in it might get into trouble, and that gives him a kind of carte blanche, he said. “Sometimes I tell them, ‘One day you might ask me for help.’”

After the court hearing Zherebenkov told The Daily Beast: “Paul was disappointed. He has a different mentality, he expected to be released on bail, that is what they do in United States.”