Warner Bros.’ “The Little Things” launches Jan. 29, marking the end of a 28-year journey for writer-director John Lee Hancock. It was worth the wait.

At various times, people attached to the project included Steven Spielberg, Clint Eastwood, Warren Beatty and Danny DeVito. “Little Things” is a classic Hollywood case of waiting for the right elements to come together.

“Back in the ‘90s,” Hancock says, “There was a lot of excitement over the script, but one executive said, ‘We’ll make the film if you change the third act.’ I said ‘That’s the precise reason I wrote it.’”

“I wanted to embrace the genre and subvert it at the same time, so it would not be formulaic but be satisfying,” Hancock adds.

The genre-bending is apparent even in the opening, when a young woman is frightened by another driver on the otherwise deserted highway. The suspenseful scene doesn’t develop the way filmgoers might expect.

“I fell in love with movies in college,” Hancock says. “It was mostly watching ’70s films, like ‘Badlands,’ ‘Downhill Racer,’ ‘The Conversation’ and any Michael Ritchie film. I liked complicated characters — and you didn’t need to answer all the questions, but you needed to ask good ones.”

“Little Things” embraces that ’70s sensibility, leaving room for audiences to debate what they’ve seen. Some have been surprised at this, but others think it’s one of the film’s strongest points.

The movie stars three Oscar winners: Denzel Washington portrays a veteran paired with a hotshot young detective (Rami Malek) as they trail a suspected serial killer (Jared Leto). Hancock did a lot of prep work with Washington and Malek, and separate sessions with Leto.

A key scene — no spoilers here — occurs halfway, with Malek grilling Leto in an interrogation room, soon joined by Washington.

“I made the decision not to have a lot of camera movement, to let the actors do the dancing,” says Hancock. “There was a lot to shoot, with multiple setups and angles and I was incredibly prepared. But I pretty much threw out my preparation and said, ‘I don’t want this to be too mathematic. There are three acts to this scene, and we can figure some of that out in the editing. So let it be messy.’ That freed the actors, and we shot it all in one day; it was pretty magical.”

Hancock also salutes his “dream team” of artisans, including DP John Schwartzman, production designer Michael Corenblith, editor Robert Frazen, composer Thomas Newman and costume designer Daniel Orlandi. All are potential Oscar contenders, as are Hancock and his three lead actors.

With so many years in limbo, “This had been in my head for almost three decades. I’d been directing scenes in my brain over and over,” he says. Shooting began in September 2019. “It was very strange, because when I finished a scene, I thought ‘I will never direct that scene again.’ Sometimes it was different from what had been in my head, and sometimes it turned out better.”

The film was produced by Hancock and Mark Johnson, whose many credits include “Rain Man,” “Breaking Bad” and “Better Call Saul.”

Hancock made his directing bow with “The Rookie” in 2000. Johnson encouraged him to direct “Little Things” himself. “At that point,” says Hancock, “we had two small children and I thought it was too dark a place to live for a prolonged time. Mark would bring it up regularly and when my kids went off to college, Mark said, ‘Now you’re out of excuses.’ I opened the script after more than a decade and was a little terrified at what I would find.”

But he was pleasantly surprised. After all that time, the script required changes of only 5-10%. “When I wrote this 28 years ago, it was pre-DNA, before a lot of forensics,” Hancock says. Among his tweaks, he cut a lot procedural explanations, since audiences are familiar with crime-scene vernacular.

“In 1992, it was contemporary, but since then, it became period movie,” he smiles. Nobody in the film has a cell phone, for example. Plus, “The script originally mentioned specific bars and flophouses. I was writing what was outside my window, because I lived in crappy apartment in Hollywood. That area has become so gentrified, the flophouse is now a Whole Foods. We had to go further into downtown, further north in the Valley.”

“Little Things” also includes a subtle tribute. When Washington’s character is searching Leto’s apartment, the TV set is on. Warner Bros. gave Hancock a list of their 1988-1990 TV series, which included “Ohara,” starring Pat Morita as a Los Angeles detective. Hancock remembered a promise he’d made in 1992 to actor Brandon Lee, Bruce Lee’s son.

Hancock says, “Brandon was a very good friend; he read everything I wrote. When he read the first draft of this, he said ‘I have to be in this movie.’ He died tragically in 1993. But I remembered Brandon had done an episode of ‘Ohara’ and we got permission from the family to use it. So I got to keep my promise.”