A former Gitmo detainee connected to last month’s ISIS attack on the Istanbul airport that killed 45 and injured more than 230 others was officially added to the U.S. government’s list of designated terrorists Wednesday.

The State Department confirmed to Fox News that Ayrat Nasimovich Vakhitov  was at the Guantanamo detention camps from June 13, 2002 until his transfer to Russia by the Bush administration in 2004.

“For an individual to be designated a terrorist by our State Department, the threshold is way high,” Tony Shaffer, a former defense intelligence officer , told Fox.  “The Pentagon has been very reluctant to release a number of individuals and has had to bow to White House and State Department pressure.”

The State Department’s announcement of the terrorist designation does not say Vakhitov was once held at Gitmo, nor does it cite his reported ties to the June attack in Turkey. The connection was first reported by the Long War Journal and independently confirmed by Fox.