As part of the 2015 international deal to freeze Iran's nuclear program, Iran and the U.S. agreed to a sort of prisoner swap.
"These individuals were not charged with terrorism or any violent offenses. They're civilians, and their release is a one-time gesture to Iran, given the unique opportunity offered by this moment and the larger circumstances at play."
But a new report in Politico says that was far from the whole story — and that several of the freed Iranians were deemed national security threats.
The Justice Department also reportedly abandoned efforts to catch 14 more fugitives, at least one of whom was strongly linked to Iran's nuclear program.
Politico quotes law enforcement officials who say the prisoner swap deal effectively sabotaged efforts to stop nuclear proliferation centered around Iran.
The Trump administration recently certified that Iran was complying with the terms of the deal. But President Trump has signaled that he'll still be scrutinizing it in the future.
Trump told reporters: "It was a terrible agreement; it shouldn't have been signed. It shouldn't have been negotiated the way it was negotiated. I'm all for agreements, but that was a bad one."