U.S. facilities were burned in a Sept. 11, 2012, attack in Benghazi, Libya, in which the U.S. ambassador to Libya and three other U.S. nationals were killed. (GIANLUIGI GUERCIA/Agence France-Presse via Getty Images)

A federal judge heard arguments Friday over whether to dismiss nearly all charges against the man accused of leading the 2012 attacks in Benghazi, Libya, that killed four Americans.

The attacks remain under investigation by a House select committee, which is set to hear testimony Thursday from Democratic presidential candidate Hillary Rodham Clinton, who was secretary of state at the time.

Libyan terrorism suspect Ahmed Abu Khattala, 53, pleaded not guilty last fall to an 18-count indictment, including death penalty-eligible charges of murder as well as conspiracy and destroying a U.S. facility, in the Sept. 11, 2012, attacks that killed U.S. Ambassador J. Christopher Stevens and three others.

On Friday, Abu Khattala — wearing headphones and a green prison jumpsuit and with a gray beard and swept-back hair — listened alertly as interpreters translated his lawyers’ arguments.

In challenging the counts, the defense said charges­ of providing material support to terrorists were so vague as to be unconstitutional and that other lesser charges applied only to domestic crimes. They also argued that the U.S. mission and annex in Benghazi were not legally recognized government facilities.

Democratic presidential candidate Hillary Rodham Clinton is to testify Oct. 22 before a House panel investigating the Benghazi attacks. Above, then-Secretary of State Clinton testified in January 2013 before the Senate Foreign Relations Committee. (Pablo Martinez Monsivais/AP)

“This motion is about government overreach,” attorney Jeffrey D. Robinson said. “Prosecutors “load[ed] up a lot of charges that don’t really matter when in fact, this is about one or two very difficult and tragic events.”

Robinson, of the Lewis Baach law firm, added: “Everyone agrees what happened in September 2012 was a tragedy and Americans suffered a tragic loss. Mr. Abu Khattala agrees it was a tragic loss but disagrees he is the person responsible for it.”

Assistant U.S. Attorney Michael C. DiLorenzo countered that federal courts have allowed prosecutions to go forward outside U.S. territory under domestic laws “enacted to allow the government to defend itself.”

U.S. District Judge Christopher R. Cooper of the District did not say when he would rule, but sharply questioned both sides about whether the government’s charges were misapplied.

“Your position is, if the president has been assassinated abroad, the government cannot prosecute it?” Cooper asked Robinson at one point. Later, he questioned DiLorenzo about where one could draw the line “if any statute intended to protect the government can apply” outside U.S. borders.

Cooper said he agreed that there appeared to be no evidence that Congress intended a law aimed at combating domestic gun violence to apply abroad. Abu Khattala could face a longer term if convicted and sentenced to prison for using a firearm while committing a felony.

Both sides agreed to postpone arguments on a defense motion challenging the constitutionality of Abu Khattala’s seizure in June 2014 by U.S. Special Operations forces in Libya and his subsequent interrogation over nearly two weeks aboard a U.S. Navy ship without a lawyer present. His attorneys have requested that he be returned to Libya or spared from the death penalty. The question is on hold pending government review of relevant classified documents.

House Select Committee on Benghazi Chairman Rep. Trey Gowdy (R-S.C.) in September said that House Majority Leader Kevin McCarthy "screwed up" when he suggested the probe was useful in driving down Clinton's poll numbers. (Cliff Owen/AP)

Abu Khattala’s attorneys have also asked permission to challenge a count of murdering a diplomat once the government decides whether to seek his execution.

No trial date has been set. Prosecutors said they expect to issue a recommendation on whether to seek the death penalty within a month of a Nov. 3 deadline for his defense to convey its views. A final decision by Attorney General Loretta E. Lynch is expected by early March.