The man whom Greene married, Denis Cuspert, is a German rapper-turned-IS recruiter.
In February 2015, the US government labelled him a specially designated global terrorist.
In one propaganda video he was seen holding a freshly decapitated human head.
Greene, who worked at the FBI's Detroit field office, was tasked in January 2014 with investigating Cuspert, according to CNN.
Six months later the German-speaking linguist travelled to Syria to marry him.
Czechoslovakia-born Greene told her work superiors she was planning a trip to visit her parents in Germany.
But instead she travelled to Turkey where she crossed the Syrian border with the help of local IS operatives, reports CNN.
Greene was still married to a US serviceman at the time.
Shortly after arriving in Syria in June 2014, she reportedly married Cuspert.
He had dropped his stage name of Deso Dogg to call himself Abu Talha al-Almani.
http://www.bbc.com/news/world-us-canada-39783511
Yep. They didn't catch that until she fled ISIS. I am sure they can easily weed out the wheat from the chaff when millions of undocumented "refugees" need to be "vetted".
