The problem was that the preview, which had been scheduled to debut before some showings of the latest Batman film that weekend, featured a peek at a pivotal moment in the 1940s true-crime romp when Los Angeles mobsters ruthlessly shoot into a movie theater audience.

Thus began an arduous odyssey to the screen of a film loosely based on violence 60 years ago impacted by the real-life violence of today — from the Colorado massacre that forced the reshooting of a key scene, through the country’s mourning following the Connecticut elementary school shooting last month, to this week’s replaying of the July theater horror in a Colorado courtroom just as the film prepares to finally open on Friday.

Fleischer couldn’t initially process what was happening in that moment when he was on the phone last summer but eventually, everyone involved with “Gangster Squad” agreed: The scene was just too similar and had to be cut — not just from the trailer, but also from the movie, which was set for release two months later.

“Many conversations followed that, and we talked about it and very quickly decided that the appropriate action would be to take the scene out of the movie out of respect for the families who suffered that loss in the tragedy,” said Fleischer. “Because we didn’t know when we were gonna come out or what was happening, we decided we have to come up with a new scene.”

So the entire movie theater sequence featuring Josh Brolin’s hard-boiled cop John O’Mara being ambushed inside famed Hollywood movie palace Grauman’s Chinese Theater was excised from “Gangster Squad.”

For many of the film’s cast and crew members, it was their favorite scene in the highly stylized gangster flick, which tells the tale of the real-life tussle between off-the-books LA police officers and an army of mobsters.

“I was really impressed with Ruben (cutting the scene) because it was the best scene in the movie,” said Ryan Gosling, who plays reluctant squad member Jerry Wooters. “There was an alchemy about it. Everything came together. It was the most cinematic part of the film because it happened in a cinema, as well, but there was just something special about it.”

The scene was filmed over four nights at the real Grauman’s and outside on Hollywood Boulevard, where the shootout between the squad and the goons of mob boss Mickey Cohen (played by Sean Penn) spilled out. The iconic theater and surrounding area was meticulously transformed for the action sequence with vintage vehicles and extras clad in period costumes.

“It was really eerie,” Brolin said of the original scene’s parallel to the real-life shooting in Aurora. “I respected and supported the decision immediately. It’s still a violent replacement. It just happens in Chinatown. It’s just as violent. It just doesn’t remind you of this thing that happened. It’s probably going to anyway because everyone knows it’s been replaced.”

Several members of the cast and crew reassembled nearly a year after filming completed on “Gangster Squad” to shoot the new sequence in LA’s Chinatown section just north of downtown.

The scene, which cost several million dollars to reshoot, fits seamlessly into the film and functions narratively in the same way as the original: Brolin’s O’Mara is ambushed, only this time by an exploding laundry truck instead of gun-toting gangsters.

The film’s debut this week coincidentally comes at the same time that 25-year-old James Holmes, who is charged with killing 12 people and injuring 70 in the July theater shooting, is appearing at a weeklong preliminary hearing to determine whether the case will be sent to trial.

“The tragedy that everyone suffered in Colorado is so much greater than having to change a scene in a movie,” said Fleischer. “I’m not gonna begin to say that I suffered as a result, just in context, it’s inappropriate. We just said, ‘We have to do this.’ Luckily, all the actors made themselves available, and we got together and we figured it out together.”

There are no current plans for the original scene to resurface, but Fleischer said he would eventually like to see it put back into “Gangster Squad” one day.

The filmmakers are also hopeful that audiences in search of entertainment this weekend won’t have any issues separating recent real-life gun violence from the bullet-ridden adventures depicted in “Gangster Squad.”

“This isn’t a movie promoting violence,” said “Gangster Squad” producer Dan Lin. “It’s a movie about unsung heroes. These characters were real guys who were doing the right thing, stopping gangsters and saving the city that we all love. Yes, in the cause of trying to save your city and take down the bad guys, sometimes the cops had to use guns.”