The trial in Washington, D.C. of Abu Khattala is over.  The Washington Post:

"A Libyan militant accused of being a ringleader of the deadly 2012 attacks on U.S. facilities in Benghazi was convicted on terrorism charges…But the jury declined to find him directly responsible for the deaths of U.S. Ambassador J. Christopher Stevens and three other Americans.'

"At trial, his defense team said Abu Khattala was drawn to the fiery scene in his home town as a bystander. They questioned the credibility of three Libyan witnesses who testified that they saw or heard Abu Khattala take steps to plan, execute and claim responsibility for the attacks.

Notably absent as witnesses for the defense were Susan Rice, Barack Obama, and Hillary Clinton.  All of them at one time or another suggested that the attack at Benghazi was caused by an offensive video, and not Abu Khattala as a ringleader of violence.  Why the defense team did not call them to testify is a mystery.

In an interview, Susan Rice once said:

[L]et's be clear about what transpired here. What happened this week in Cairo, in Benghazi, in many other parts of the region ... was a result – a direct result of a heinous and offensive video that was widely disseminated ... which we have made clear is reprehensible and disgusting[.]

Barack Obama is on record saying:

[W]hat we've seen over the last week ... is something that actually we've seen in the past, where there is an offensive video or cartoon directed at the prophet Muhammad. And this is obviously something that then is used as an excuse by some to carry out inexcusable violent acts directed at Westerners or Americans.

Kelly Riddell wrote in The Washington Times for Tuesday, June 28, 2016:

Another day goes by, and publicly Mrs. Clinton continues to blame the internet video in her remarks[.] ... On Sept. 14, White House spokesman Jay Carney, answering a question about Benghazi during a press conference, said: 'We have no information to suggest that it was a preplanned attack. The unrest we've seen around the region has been in reaction to a video that Muslims, many Muslims find offensive[.]'

Even though Khattala's trial featured "dramatic testimony by surviving State Department and CIA operators, some taking the stand under fake names and disguised in wigs and mustaches to protect their identities," no one from the defense team saw fit to call Rice, Obama, and Clinton to testify.

After the trail, "Dana J. Boente said in a statement that, "'...Our work is not done. We will not rest in our pursuit of the others' involved in the attacks."

At the end of the trial, Abu Khattala was found not guilty of ambassador Stevens's murder.

So far, no one else has been charged with Stevens's death.

Maybe that's because we still don't know how Stevens died.  Spencer S. Hsu and Ann E. Marimow write in their Washington Post article that "Stevens ... died of smoke inhalation[.]"

There is no proof for this.  The Stevens autopsy was not made public at the trial.  His cause of death is speculation on the part of the media.

In spite of Abu Khattala's trial and pending verdict, we still don't know answers to three lingering questions about the incident at Benghazi.

How did ambassador Stevens die?

Who killed him?

What was the motive?