Ahmadreza Djalali isn't a Swedish citizen but he and his family legally reside here. He was affiliated with Stockholm's Karolinska Institute until 2016.
Iran claims Djalali was spying for Israel in return for Swedish residency. But activists say the evidence against him is flimsy or non-existant.
Maja Åberg is an advocacy officer at Amnesty International Sweden. Her group is one of several that are calling for Djalali's release.
"We're hoping that by doing this we will be able to shed a spotlight on his case," Åberg says. "In the end, ofcourse, we hope that he will be released."