There are reports circulating that the attack on the American consulate in Libya may have been planned ahead a time, and used the backlash from the film as cover for the operation.
BBC security correspondent Frank Gardner says Arab officials believe the Benghazi attack was in fact planned ahead of the film.
The building apparently came under attack by a crowd armed with guns and rocket-propelled grenades, after which Ambassador Stevens and his staff went to the consulate in an attempt to evacuate the site, the Associated Press reported.
Dr Ziad Abu Zeid, the Libyan doctor who treated Stevens in hospital, told the BBC he died of severe asphyxiation, apparently from smoke inhalation, with no other injuries.
Initial accounts of the assault in Benghazi were attributed to popular anger over what was described as an American-made video that lampooned the Prophet Muhammad, which had been publicized by Egyptian media and led to a mob protest at the United States Embassy protest in Cairo on Tuesday. But administration officials in Washington said the attack in Libya may have been plotted in advance.
While the protesters in Cairo appeared to be genuinely outraged over the anti-Islam video, the attackers in Benghazi were armed with mortars and rocket-propelled grenades. Officials said it was possible that an organized group had either been waiting for an opportunity to exploit like the protests over the video or perhaps even generated the protests as a cover for their attack.
There are also unanswered questions concerning the film itself.
A more complex picture since emerged since the early analyses of the film as a crude anti-Islam diatribe. It now appears likely that all references to Islam in the dialogue were spoken not by the actors but were dubbed over in post-production.
It now appears possible that the actors did not know the film would eventually deal with such controversial subject matter - and did not themselves speak the lines that made the film the provocative and insulting production that most commentators agree it is....
The performers are not well-known actors and some appear to be amateurs. The film was shot on video, much of it clearly against green screen with the backgrounds dropped in afterwards.
Initial reports - including in this article - identified the producer of the film as Sam Bacile, "who describes himself as an Israeli real-estate developer living in the United States".
The Wall Street Journal reported he had made the film with $5m (£3m) raised from 100 Jewish donors. In a phone interview, Mr Bacile was said to have described Islam as a "cancer", and said the film was political and not religious.
But extensive efforts by BBC reporters to trace Mr Bacile - through his credentials as a filmmaker or a real-estate agent - have so far proved fruitless.
Israeli officials quoted anonymously by Associated Press have also said there is no record of an Israeli citizen of that name.
The Atlantic spoke to a man identified in multiple media reports as a consultant to the film, Steve Klein, who claimed that "Mr Bacile" was, in fact, not Israeli, probably not Jewish, and that the name was a pseudonym.
The only reference to Sam Bacile on the internet prior to last week was the Youtube user "sambacile" who posted the 14-minute trailer of the English version of the film at the beginning of July.
This user's account was set up on 4 April 2012, according to Youtube information.
The Wall Street Journal identified the filmmaker as Sam Bacile, an Israeli-American real estate developer -- but by Wednesday afternoon, doubt surfaced over whether anyone by that name even exists.
The Journal reported that, in its telephone interview with Bacile, he characterized his film called "Innocence of Muslims" as "a political effort to call attention to the hypocrisies of Islam."
"Islam is a cancer," he told the newspaper. "The movie is a political movie. It's not a religious movie."
CNN has not been able to contact Bacile and cannot independently verify his claim that he made the movie. A CNN search of public records on Sam Bacile came up empty.
Israel's Foreign Ministry said it doesn't know who Bacile is.
"This guy is totally anonymous. At this point no one can confirm he holds Israeli citizenship and even if he did we are not involved," ministry spokesman Yigal Palmor said. "No Israeli institution, government department or office has any involvement in this. This guy acted on his own behalf."
Update at 8:48 p.m. ET:
Using the cellphone number they talked to "Sam Bacile," The Associated Press tracked down a man named Nakoula Basseley Nakoula, 55, who lived at the address that aligned with cellphone records.
Nakoula denied that he directed the film but admitted that he was the manager for the production company. He also told the AP that he was a Coptic Christian.
The AP notes that Nakoula has a criminal record: He pleaded no contest in 2010 to federal bank fraud charges and served 21 months in federal prison.
The AP adds:
"Nakoula denied he had posed as Bacile. During a conversation outside his home, he offered his driver's license to show his identity but kept his thumb over his middle name, Basseley. Records checks by the AP subsequently found the name 'Basseley' and other connections to the Bacile persona.
"The AP located Bacile after obtaining his cell phone number from Morris Sadek, a conservative Coptic Christian in the U.S. who had promoted the anti-Muslim film in recent days on his website. Egypt's Christian Coptic population has long decried what they describe as a history of discrimination and occasional violence from the country's Arab majority."
The NPR story also confirms that Terry Jones has played a role:
When clips of the film were shown on an Egyptian TV program, they were described as being the work of Terry Jones, the Florida pastor who has burned Qurans. Jones, The Wall Street Journal reports, was merely promoting the film, saying he would screen the trailer at his church on Sept. 11.
"The film is not intended to insult the Muslim community, but it is intended to reveal truths about Muhammad that are possibly not widely known," Jones said in a statement obtained by The Orlando Sentinel.