MOSCOW — Months have passed since Russian police detained a former U.S. Marine, Paul Whelan, in his hotel near the Kremlin, and both governments have gone strangely silent about his fate as speculation swirls about a high-level U.S.-Russian prisoner swap. Even Russian analysts see Whelan as a virtual hostage, held on espionage charges so cloaked in secrecy that his defense lawyer cannot speak about them.

On Friday, a Moscow court extended Whelan’s pretrial detention in Lefortovo prison until August 28, and Whelan spoke up. He denounced Aleksei Khishnyak, an investigator from the the FSB, the successor agency to the KGB. "He has insulted my dignity, he threatened my life," Whelan told journalists in the courtroom on Friday morning.

Judge Sergei Ryabtsev explained to the American defendant that under Russian law Whelan cannot demand that an investigator be dismissed.

"I understand that but what am I supposed to do if he abuses my rights?” Whelan asked. “He does not behave as a professional.”

After the court hearing The Daily Beast spoke with Whelan’s defense lawyer, Vladimir Zherebenkov.

"Whelan has not had a chance to shower in two weeks,” Zherebenkov said. “He was not provided medical service when he needed it. The FSB investigator mocks him with little jokes. You see, my client believes that by mistreating him the investigation puts pressure on him."

The attorney says that it is obvious that the FSB has no evidence against Whelan.

"Believe me, I have many years of experience dealing with the FSB. They always roll out what they have, but in this case, we've seen nothing concrete against Whelan in five months. That means there is nothing."

Paul Whelan’s twin brother David says that unlike other Lefortovo prisoners, Paul is prohibited from using the phone and that would be the case “until Paul ‘cooperates with FSB,’ his words not mine,” David Whelan told The Daily Beast. If they are looking for a confession, it seems they are not going to get it.

“We expect his detention to be continued into August, then probably November, probably February again. There is no evidence to support the allegation, so there is no logical conclusion to his detention,” said David Whelan.

The date of the trial also is a secret, meaning his detention could go on well beyond the summer.

Why does Moscow have Whelan behind bars?

Paul Whelan is 49-year-old director of global security and investigations at BorgWarner, a Michigan-based manufacturer of automotive parts. According to Whelan’s lawyer and his family, the former Marine was visiting Russia for a friend’s wedding in December, when the FSB detained him on December 28 in Moscow’s Metropol Hotel. He was charged with espionage, punishable by 20 years in prison.

Whelan, like many Westerners, has long been fascinated by Russian culture and the Russian military. (The Spetsnaz special forces have a special mystique.) And he had made contact with some Russian soldiers on social media, which is easily done. That is not in itself incriminating, although it may have attracted the attention of the FSB. Somewhat more unusual, Whelan has four passports (British, Canadian, and Irish as well as U.S.). In 2006 he was kicked out of the Marines with a bad conduct discharge for “attempting to steal” $10,410.59 from the U.S. government.

People who have examined the case in Russia suggest Whelan's arrest looked like a set-up. A friend handed him a thumb drive when they met in his hotel. Whelan says he thought it contained pictures of a tourist trip they had taken together, but the FSB showed up and arrested him before he even opened the files. Prosecutors claim there was classified material on the drive.

Whelan’s arrest came less than two weeks after Maria Butina admitted in the U.S. court that she was part of a Russian effort to influence U.S. politics, and the timing suggested that Whelan’s arrest was Moscow’s revenge, or a move to make a deal, since experts on U.S. intelligence were skeptical that Whelan had affiliations with any intelligence agency.

“If the detention is not appropriate we will demand his immediate return,” Secretary of State Mike Pompeo vowed in January.

“ We are frustrated that Paul–or any American–can be mistreated by Russian authorities who ... falsely arrest and wrongfully detain our brother and son without apparent consequences. ” — David Whelan, the prisoner's brother

But nothing has happened immediately, and in fact Butina will be out of prison soon with or without the release of Whelan. She was accused of attempting to infiltrate conservative political groups close to Trump by working through her contacts with the National Rifle Association. She took a plea deal and is serving an 18 month sentence for conspiracy to act as an unregistered foreign agent. With time already served before her sentencing, she could be released by the end of this year or early 2020, at which point she will be sent back to Russia.

Tass, Russia’s major news agency, has reported that Russian officials have identified 12 of their citizens they believe are held illegally in the United States. Whelan might be traded for one or more of them.

The Russian prisoner in the United States with the highest profile is arms dealer Viktor Bout, one of the world’s most infamous merchants of death. He reportedly was the inspiration for the 2005 Hollywood film Lord of War . After American agents caught up with him in Thailand, he was brought to the U.S. and convicted in 2011 for conspiring to sell weapons to terrorist organizations and sentenced in 2012 to 25 years in prison. The Russian government and media frequently call for his release.

An expert on Russian prisons, Zoya Svetova believes that “the hostage” Whelan has been kept by President Putin to be swapped for some such senior Russian prisoner. “Now Butina will be free in a few months anyway, maybe even before Whelan’s trial begins,” Svetova told The Daily Beast. “So it might be the arms dealer Viktor Bout, who Putin wants to swap for.”

Another potential exchange, and a more likely one, would be for Russian pilot Konstantin Yaroshenko, who’s been behind bars in United States since 2010, sentenced to 20 years in prison for conspiring to smuggle cocaine. He apparently is very much on the minds of Russian authorities. The Kremlin has been asking President Donald Trump to pardon Yaroshenko.

Russian Commissioner for Human Rights Tatyana Moskalkova said explicitly that she hoped Trump could swap 50-year-old Yaroshenko for a U.S. citizen. Last year Yaroshenko met with his family for the first time in seven years. His daughter complained that his health was failing.

Whelan’s family hoped Pompeo would shed some light on the case after meeting with President Vladimir Putin earlier this month. On Pompeo’s trip to Russia he said after his meeting with Russian Foreign Minister Sergey Lavrov that he had “ raised the issue of U.S. citizens who have been detained in Russia, making sure that our citizens are not unjustly held abroad.” Pompeo said, “It is one of President Trump’s highest priorities.”

David Whelan says that since then he has been waiting for word. “No news,” he told The Daily Beast. “All they shared was Secretary Pompeo’s statement that some Americans detained in Russia had been discussed but no mention of any specific American by name.”

Whelan is not the only American entangled in a criminal case in Russia. Last February Russian authorities arrested the top U.S. investor here, Michael John Calvey. Unlike Whelan, who is kept in a two inmate cell at Lefortovo prison, Calvey is under house arrest.

With attention to the Whelan case fading, the founder of the“Russia Behind the Bars” NGO, Olga Romanova, says that Whelan might spend more than a year in pre-trial detention. "Nobody can help Whelan now, most people have forgotten about him,” Romanova told The Daily Beast.

“Our activists cannot help him much to put pressure on the authorities – it is too late, there is no public interest in his case.”

So Whelan is now languishing in one of Moscow’s worst jails and his twin brother David Whelan has heard little since December.

“We are frustrated at the lack of information and that it is an obstacle to getting Paul home–that includes frustration that the U.S. State Department does not appear to have the tools necessary to find out what they need to in order to trigger diplomatic and other means to get Paul home,” David Whelan told The Daily Beast. “But it is not just the State Department. We are frustrated that Paul–or any American–can be mistreated by Russian authorities who use a notional ‘rule of law’ process to falsely arrest and wrongfully detain our brother and son without apparent consequences.”

The United States and Russia, of course, have much else on the agenda, from North Korea to Iran to Venezuela. And to the discouragement of Whelan’s supporters, Kremlin propaganda has been preparing Russian audiences for Trump’s vaunted “art of the deal” to fail on several fronts, possibly including prisoner swaps.

“I have the impression that Trump thinks he lives in a fairytale,” influential propagandist Dmitry Kiselyov said recently on his weekly news show, referring to the bigger picture. “He takes Iran for a magic lamp, which he rubs to make the genie fulfill his dreams,” Kiselyov said, but instead he’s going to release “the nuclear genie” by “looking for war.”

So the Whelan family waits, and wonders. All they are looking for is Paul to come home.