A 28-year prison sentence is too lenient for a Libyan who was convicted of terrorism-related charges in the 2012 attacks on U.S. compounds in Benghazi, Libya, that killed Ambassador Chris Stevens and three other Americans, a federal appeals court ruled Friday.

A three-judge panel from the U.S. Court of Appeals for the District of Columbia Circuit threw out Ahmed Abu Khatallah's sentence and transferred the case back to the district court in Washington, D.C., for resentencing.

A district court judge initially sentenced Khatallah to a 22-year prison sentence in 2018, but the appeals court rejected it four years ago as a "shockingly" light punishment under the circumstances. The appeals court panel concluded that the 28-year sentence, which U.S. District Judge Christopher Cooper, an Obama appointee, handed down in 2024 remains unreasonably lenient.

The D.C. Circuit judges said a 28-year sentence does not reflect the seriousness of Khatallah's crimes.

"Khatallah helped prepare for and execute a premeditated, armed attack on a U.S. diplomatic outpost. He pressured a Libyan security force not to patrol the Mission during the attack. And his only stated regret was that the terrorists did not kill every American at the Mission," the appellate ruling stated.

The latest appeal was decided by Judges Karen LeCraft Henderson, J. Michelle Childs and Florence Pan. Henderson was appointed by George H.W. Bush and Childs and Pan were appointed by Joe Biden.

Khatallah was captured in 2014 and convicted of multiple terrorism-related charges after a 2017 trial, but the jury acquitted him of murder.

The Benghazi attack became a political flashpoint in Washington. A Republican-led congressional panel's report blamed the Obama administration, including then-Secretary of State Hillary Clinton, for security failures and a slow response to the compound attacks.