Guantanamo Bay detention camp
Mansoor Adayfi lives under near-constant surveillance in Serbia and his legal status in the country is uncertain.
A former hostage said he and victims' family members oppose the possibility.
Detainees usually receive a decision about a month after their parole-style hearings. Omar Muhammad Ali Al-Rammah has waited more than a year.
Trump pledged during his campaign to repopulate the prison, saying he wanted to “to load it up with some bad dudes.”
They transferred 201 detainees, but the president didn't keep his promise to shut down Guantanamo.