Washington (CNN) The Justice Department said Tuesday it won't seek the death penalty for Ahmed Abu Khatallah, the Libyan militia leader accused of helping to carry out the attacks on the U.S. diplomatic and CIA facilities in Benghazi in 2012.

Federal prosecutors made the notification in a filing with federal court in Washington, where Khatallah faces trial related to the attacks that killed four Americans, including U.S. Ambassador Christopher Stevens.

He was captured in a raid by U.S. commandos in Libya in 2014 and brought to United States on a U.S. Navy ship that allowed for an FBI-led team of interrogators to question him. He has pleaded not guilty.

Khatallah's case has been at the center of controversy, in part because some critics of the Obama administration objected to the use of the civilian justice system to handle his detention. The Benghazi attacks, and the U.S. response led by then-Secretary of State Hillary Clinton, led to congressional hearings and since then spawned a separate political controversy over Clinton's use of a private email server during her time in office.

In interviews with journalists following the Benghazi attacks, Khatallah denied carrying out attacks that killed Americans.

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