Russian authorities have sent imprisoned Michigan native Paul Whelan to “a strict regimen camp” established “as part of the gulag under Stalin,” according to the former Marine’s twin brother.

“He's really into the unknown,” David Whelan told the Washington Examiner.

Whelan has been sentenced to 16 years of imprisonment on charges of espionage based on allegations that his family says were trumped up by Russian security services with the assistance of a supposed friend who owed him money. His family believes that Russian President Vladimir Putin’s government wants to swap Paul Whelan in a prospective deal involving high-profile Russian criminals in American prisons, but U.S. officials have dismissed the idea of a trade.

“We seem to be at sort of an impasse where if there are discussions going on, it's not clear they're going on,” David Whelan said. “And in fact, Paul being sent out to the labor camp suggests that there aren't any activities going on between the two countries.”

The lack of communication was evident on Monday, when State Department officials made a routine inquiry about Paul Whelan’s status at Lefortovo Prison only to learn that he “wasn’t there anymore.” Prison authorities declined to provide any information about his whereabouts to the U.S. government, his brother said, but they told British officials on Tuesday that he had been sent by train to a camp in Mordovia.

“It is no surprise that once again the Russian authorities violated Russian law, by failing to notify our family about Paul's whereabouts,” David Whelan wrote in an email to journalists and supporters. “It also shows how easily American citizens held in Russia can disappear from view, as consular access is now even more curtailed than it has been since Paul was first wrongly detained.”

Conditions at the Mordovia camps, “the only island of the Gulag archipelago which prevailed,” as Russian dissident Pyotr Verzilov recalled in 2013, can be brutal.

"There are many sayings among prisoners who served out their sentences in one of these prisons in the Mordovlag: 'If you’ve been to a prison camp in Mordovia, hell will seem like a rather elegant resort,'" Verzilov — whose wife, Pussy Riot member Nadezhda Tolokonnikova, spent nearly two years at a Mordovian facility — quoted the prisoners as saying of the place.

David Whelan expressed a paradoxical optimism that his brother might benefit from being moved there after nearly 20 months in a Moscow jail. “Even though it's a strict regimen camp, that is possibly better than being in Lefortovo,” he said. “The pre-trial detention centers in Moscow are pretty awful.”

At Mordovia, Paul Whelan seems likely to be forced into “some sort of light industrial labor” with only quarterly opportunities to receive mail from his family and “highly constrained” access to American diplomats. “It sounds like the strict regimen actually applies to how strictly the prisoners are treated,” his brother said. “And if he falls afoul of the prison camp authorities, he can be put into ... almost like a solitary confinement environment within the camp.”

The experience of the camp is almost a literal legacy of the Soviet Union’s oppression, with “family dynasties,” as David Whelan put it, of prison guards who work the same jobs that their grandparents held.

“The brutal traditions passed from grandfather to father to son and became infamous across the Soviet Union, with most prison officials in the Mordovian prison system of the belief that they are still living in a Soviet-style reality, frozen somewhere around the mid-1970s,” Verzilov wrote in 2013.

David Whelan said he’s not sure if his brother’s transfer to that place is “a negotiating tactic” meant to apply pressure to the State Department or a sign that his case is intractable.

“We're in a little sailboat floating in a big sea with not a whole lot of indicators of which way to go or what’s going to happen next,” he said.