The FBI has identified 44-year-old British national Malik Faisal Akram as the hostage-taker.

An officer who spoke to The Associated Press anonymously said the hostage-taker was heard demanding the release of Aafia Siddiqui, a Pakistani neuroscientist currently serving an 86-year sentence in a Texas prison.

Siddiqui tried to kill U.S. soldiers and FBI agents while in custody in Afghanistan. She was arrested in 2008 after being listed on the FBI’s Most Wanted List.

Her arrest and conviction is widely criticized in Pakistan where she is seen as being wrongfully imprisoned.