A man seized by US forces in Libya and accused of playing an instrumental role in an attack that killed US Ambassador Christopher Stevens in Benghazi in 2012 made his first appearance in federal court on Friday in Washington, where he was ordered held until a hearing next week. Judge Deborah Robinson of the US District Court for the District of Columbia ordered Mustafa al-Imam held pending a preliminary hearing on Thursday, the DC federal prosecutors office said. Al-Imam arrived in Washington earlier on Friday, the office said in a statement. He was wearing an orange jumpsuit and listening to the court proceedings through an ear piece as they were translated from English. A criminal complaint attached to the statement and dated May 19, 2015, said he has been charged with "killing a person in the course of an attack on a federal facility" and providing "material support to terrorists resulting in death." US officials have said that al-Imam was arrested Sunday night in Libya’s third-largest city of Misrata and was transferred to the US. The US Justice Department has said the charges against him stem from the Sept. 11, 2012 attack on a US diplomatic compound in Benghazi in which Stevens and three other Americans were killed. The Benghazi attack became emblematic of conservative opposition to then secretary of state Hillary Clinton. Several congressional investigations were launched, along with a State Department security review, into both the handling of the attack and how it was described in the media. Clinton was never convincingly tagged with wrongdoing or negligence, but the issue haunted her failed 2016 presidential campaign and may have contributed to Trumps victory.