"The two imprisoned Americans offered distinct cases that were eventually linked and then unlinked. Ms. Griner, detained on minor drug charges a week before Russia’s invasion of Ukraine, a former Soviet republic, was seen as a hostage in the midst of the confrontation with the West over the conflict. Mr. Whelan, a former U.S. Marine, had been in prison since 2018 on espionage charges long before the war in Ukraine."

https://www.nytimes.com/2022/12/09/us/politics/brittney-griner-prisoner-swap.html