Michael Bay’s “13 Hours: The Secret Soldiers of Benghazi” opens with the message, “This is a true story.”

In other words, not “based on a true story,” but “a true story.”

Given the political controversy that has swirled around the events of the Benghazi attacks for more than three years, the movie is destined to be heavily scrutinized for how it portrays the team of six security contractors housed at a secret CIA annex in Benghazi, Libya. It shows how they put their lives on the line to respond to the Sept. 11, 2012, attack on the nearby diplomatic compound.

The contractors have said that they wanted to see their story told on screen because the politics surrounding Benghazi have obscured the actual events on the ground that evening as well as the lives that were lost. Four Americans, including U.S. Ambassador Chris Stevens, were killed.

“Probably the biggest challenge was remaining completely true to the events that transpired that night,” said producer Erwin Stoff. “Any time you are doing a real story or a true story, there is that temptation to say, ‘Well, it would be better if this would happen or that would happen.’ But there is not a thing in this movie that is not verifiable by two or more sources.”

The movie’s origins came just months after the attacks, Stoff said, when Richard Abate, book agent with Stoff’s 3 Arts Entertainment, was put in touch with Kris “Tanto” Paronto, one of the security contractors. “We got all five [contractors] together and we all realized there was a book there and eventually a movie,” Stoff said.

After a bidding war between a number of publishers, a Hachette imprint got the book, and Mitchell Zuckoff was hired to write it with the security team.

Other Benghazi film projects began to surface, so instead of waiting until the book was published, they began to develop and pitch the movie beforehand. Four of the contractors came with them to pitch the studios.

“They, as much as anybody, told the story,” Stoff said.

Paramount bought it, with Chuck Hogan writing the script and Bay attached by August, 2014, Stoff said. Other studios said it “was one of the most compelling pitches they had heard but everybody was reluctant about the politics of it.”

The book, “13 Hours: The Inside Account of What Really Happened in Benghazi,” was published that September.

“The biggest challenge was getting it right,” Zuckoff said.”I felt very deeply that so much false information had flown around this that if this book had even a small error we would be doing a disservice to them and to their service.”

Production started in April, 2015, including nine weeks in Malta and one week in Morocco.

Perhaps no other moment in the movie has been as hotly debated as the contractors’ assertion that they were given an order to “stand down” by the CIA annex chief, a wait of about 20 minutes before responding to the attack at the nearby diplomatic mission where Stevens was quartered. Eventually they bucked orders and left.

The contractors insist that a “stand down” order was given, even though the CIA has denied it and congressional investigations have so far found that none such order was given, even if there was a delay as the CIA chief sought out a local militia. (The chief’s identity is not revealed in the movie, and he is named “Bob”). Another report is expected this spring from a House special committee on Benghazi, and the issue is expected to be raised again, according to Politico. 

The issue is important because some of the contractors believe that if they had gotten their sooner they could have saved Stevens and Sean Smith, an information management officer who was killed.

The contractors “heard the calls immediately,” Zuckoff said. “No one has disputed that they ‘jocked up’ — in their lingo, they armored up immediately and they staged these cars ready to go. And then 20 minutes go by. There’s no question that Bob was trying to get help from the local militia forces. And so the delay did take place and the guys ultimately went on their own.”

Zuckoff said that he believes what the CIA chief was doing was “sincerely trying to gather forces, but it was a misguided effort.” The problem, he said, was that the militia was unreliable.

“We have never heard anything from the CIA other than, ‘No [the stand-down order] didn’t happen.’ These guys [the security contractors] are putting their lives and their reputations on the line saying, ‘We were forced to wait, and the record shows it.'” A problem, he said, was that the CIA chief was a spy, not a military tactical commander.

The book and the movie do not suggest what some conservative critics have — that the “stand down” order came from higher ranks, perhaps from the White House.

“We are not claiming that there was some order from on high, that there was some kind of overarching order out of Washington or even out of Tripoli,” Zuckoff said. “The book makes clear and the movie absolutely does, it absolutely gets it right, that these are fast-paced decisions, and they turned out to be wrong decisions.”

The movie also portrays Stevens’ belief in the U.S. engagement in Libya and assistance in transforming itself from a dictatorship, but at the same time some of the cynicism of one of the contractors.

“They had all been in this region for a decade, and had seen it become more violent and less democratic,” Zuckoff said. “And so whether it was cynicism or exhaustion — it definitely had set in. Having said that, they also had great respect for Chris Stevens. We all should respect Chris Stevens, who dedicated his life to trying to improve relations between the Arab world and the western world.”

As much as has been written and investigated about Benghazi, Zuckoff says that part of the story still remains a big mystery — the identities of all of the insurgents who attacked the compound and shelled the CIA annex that evening. Ahmed Abu Khattala, a leader of Ansar al-Sharia, was caught and is suspected of being one of the ringleaders of the attack.

“We need to get at the source of this,” Zuckoff said. “We need to find out about all of them. We need to understand exactly their motivations, with the idea of preventing it” from happening again.