A Libyan militant convicted in the 2012 Benghazi attack that killed four Americans, including an ambassador, was given an “unreasonably low” sentence of 22 years in prison, a federal appeals court ruled Tuesday. Ahmed Abu Khattala, 51, was found guilty of four federal terrorism charges in 2017, with a jury deciding he’d put lives in danger by joining in on the attack, which saw several militant groups overrun a U.S. special diplomatic mission and shell an adjacent CIA facility. But the panel had doubts as to whether Khattala was responsible for the deaths of any of the Americans, including Ambassador Christopher Stevens, and acquitted him on 20 of the most serious charges against him. Khattala launched an effort to overturn his conviction soon after, but his appeal ended disastrously this week, with a panel of appellate judges finding his sentence “substantively unreasonably low in light of the gravity of his crimes of terrorism.” Calling it “shockingly low and unsupportable,” the D.C. Circuit Court of Appeals ordered his case be sent back to a lower court for another sentencing.