US prosecutors have accused a former US Air Force officer of spying for Iran in an elaborate operation to target her fellow intelligence officers.
Monica Witt, who reportedly defected to Iran in 2013, had previously worked as a US counterintelligence officer.
Four Iranian citizens have also been charged with attempting to install spy software on computers belonging to Ms Witt’s colleagues.
According to the FBI, Ms Witt was last seen in southwest Asia in July 2013.
A previously issued FBI missing persons poster said she was working as an English teacher in either Afghanistan or Tajikistan, and had lived overseas for more than a year before vanishing.
Prosecutors say Ms Witt, a former Texas resident, had been granted the highest level of US security clearance and worked in the US Air Force from 1997 to 2008.
Assistant Attorney General John Demers, the head of the US Justice Department’s national security division, told AP News: “It is a sad day for America when one of its citizens betrays our country.”
The US Department of Treasury has also sanctioned two Iranian companies – New Horizon Organization and Net Peygard Samavat Company – for their role in the plot.
Investigators say Ms Witt was recruited after attending two conferences hosted by New Horizon Organization, which was working on behalf of the Iranian National Guard’s Quds Force.