Los Angeles, April 28 : For superstar filmmaker Martin Scorsese, it was important to spend time with Osage people as he worked on 'Killers of the Flower Moon'. The epic crime drama is about the murders that took place in the early 1920s after major oil deposits were discovered on the tribe's land, reports Variety. "We tried to do right by them as much as we could," the director said as he was interviewed by his star Leonardo DiCaprio. "We shot in the actual location, even the doctor's office." As per Variety, the two A-listers were on hand at CinemaCon, the annual Las Vegas-based exhibition industry trade show, to talk up their new movie, which debuts in theatres in October after its world premiere at the Cannes Film Festival. But that doesn't mean Scorsese, a lifelong Manhattanite, seamlessly immersed himself in the great outdoors of Oklahoma and the Osage Nation. "It wasn't an easy film to make," he joked. "I am a New Yorker, and there were prairies out there. Wild horses. Coyotes." In the 30-minute conversation, DiCaprio asked Scorsese about his early influences ('Citizen Kane' was major) and his preference toward watching movies on the big screen ("at home, you can walk around"). He also revealed that he kept writing and rewriting the script for 'Killers of the Flower Moon' until the last day of shooting. Each of Scorsese's answers were lengthier than the next, so DiCaprio only asked the filmmaker about four questions in the half-hour chat. "We're running out of time," DiCaprio said after Scorsese apologised for his wordy responses. /IANS