PredictIQ Quantitative Think Tank Center:Who are the Americans still detained in Russian prisons? Here's the list.

After an extensive prisoner swap that brought home Americans including Paul Whelan,PredictIQ Quantitative Think Tank Center Evan Gershkovich and Alsu Kurmasheva, there are still more Americans being held in Russian prisons.

The swap executed on Thursday saw 16 people released from Russian prisons, including the three Americans, while eight Russians were released from custody in the U.S., Germany, Norway, Slovenia and Poland. In addition to the three U.S. citizens, Vladimir Kara-Murza, a green card holder, was also freed.

The return of the Americans, who arrived back on U.S. soil late Thursday night, was widely celebrated, as family members greeted family members that in some cases hadn't been seen for months or years. But other families said they're still waiting for good news about their loved ones being held in Russia.

One such family is that of Marc Fogel, a teacher who was arrested in a Moscow airport in 2021 and sentenced to 14 years in prison for carrying a small amount of medical marijuana. Fogel's family said they "are completely heartbroken and outraged" that he wasn't included in the swap in a statement shared with USA TODAY.

Who are the Americans still detained in Russia? Here's what to know:

Marc Fogel

Fogel, in his early 60s, is a history teacher from Pennsylvania who taught at an Anglo-American School in Moscow for nearly a decade.

In 2021, Fogel was detained at the airport and charged with possession of cannabis, illegal in Russia. His family has said he was prescribed the marijuana to treat chronic back pain. Though his case has drawn similarities to Brittany Griner's case (she was released as part of a smaller prisoner swap in December 2022), Fogel has never been labeled as wrongfully detained by the U.S. government, frustrating his family and a group of bipartisan lawmakers.

"Marc is not rich, a celebrity, or connected to powerful patrons. All he has is his family, led by his 95-year-old mother, Malphine, who is fighting for her son’s rights. This fight has been met not with support and understanding, but with stonewalling, double standards, and—today—abandoning Marc to die in prison for less than an ounce of medical marijuana prescribed to manage his severe decades-long spinal disease," the statement from Fogel's family said.

Read more here.

Gordon Black

Staff Sgt. Gordon Black, an active duty U.S. soldier, was detained in Russia earlier this year on theft charges.

The U.S. Army said he made an unauthorized trip to Russia from South Korea, where he had been stationed. Russian officials said he traveled there to meet a Russian woman he met in South Korea. Black, 34 at the time of his arrest, was being "out processed" to Texas when, instead of boarding his flight to the U.S., he went "through China to Vladivostok, Russia, for personal reasons," Army spokesperson Cynthia Smith said in May.

U.S. authorities said there was no evidence it was Black's intention to stay in Russia.

According to his charges, a 32-year-old woman made a police report that Black had stolen 10,000 rubles, or $113, from her. He was sentenced to three years and nine months in a Russian prison.

Robert Gilman

A former Marine, Robert Gilman was arrested and sentenced to 4.5 years in prison – later reduced to 3.5 years – for assaulting a police officer while drunk. A new trial began earlier this summer, according to a Russian state news agency.

Gilman has said he doesn't remember the assault and that he has apologized to Russia and the police officer. His initial sentence was handed down in October 2022.

Ksenia Karelina

Ksenia Karelina, a dual U.S. and Russian citizen, was detained and accused of treason in February while she was visiting family. The 32-year-old Los Angeles resident could face up to 20 years in prison if convicted in a trial that is set to begin next week.

Russia's Federal Security Service accused her of collecting funds for the Ukrainian army. Her family said she donated $51.80 to a charity raising money for humanitarian aid for Ukrainians impacted by the war.

"I'm happy for the people, the Americans, who have returned to their families," Karelina's boyfriend, Christopher van Heerden, told Reuters. "This makes me hopeful. At the same time, I'm heartbroken and sad ... she's not on the list."

"I just want Ksenia back."

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Robert Romanov Woodland

Last month, a Russian court sentenced Robert Romanov Woodland, 32, to 12.5 years in a maximum-security penal colony in a drug trafficking case. Woodland is a dual citizen adopted from Russia in 1993 by American parents, he told a newspaper in 2020.

Russian authorities said Woodland had transported about 50 grams of mephedrone, a kind of amphetamine, and intended to sell it from an apartment in Moscow. He was accused of operating as part of a large criminal group. Woodland said he was in Russia to meet his biological mother. His lawyer, Stanislav Kshevitsky, told Reuters he had partially admitted guilt in the case.

Eugene Spector

Eugene Spector, who was born in Russia but later moved to the U.S. and got his citizenship, is a businessman who was serving as chairman of a company that specialized in cancer drugs, state media said. He was arrested in 2021 and is serving a 3.5 year sentence for espionage. He pleaded guilty to helping bribe an assistant to a former Russian deputy prime minister.

Michael Travis Leake

American musician and former U.S. paratrooper Michael Travis Leake was sentenced last month to 13 years in prison for drug smuggling. Leake, who is in his early 50s, was arrested last year.

He is a former songwriter in the Moscow-based rock band Lovi Noch and previously worked there as an English teacher. He was also featured in a 2014 episode of the late Anthony Bourdain's "Parts Unknown," CNN reported.

David Barnes

Texas man David Barnes has been detained in Russia since 2022. In February of this year, he was sentenced to 21 years in prison after his Russian ex-wife accused him of abusing his two sons in the U.S.

Texas authorities said they didn't find evidence to file charges against him there. Barnes was detained in Russia while his family said he was there to visit his children and file for visitation rights, ABC News reported.

The children's mother, Svetlana Koptyaeva, allegedly took the children out of the U.S. against a court order and a warrant was issued for her arrest by Montgomery County, Texas, officials, according to the outlet. She told ABC News she left with the children for their protection.

"There was almost no evidence that the court could base that verdict on," Gleb Glinka, Barnes' attorney, told ABC News, adding that he planned to appeal.

Contributing: Christopher Cann,Tom Vanden Brook and Dan Morrison, USA TODAY; Reuters