Actor Isaiah Washington, left, and director Alexandre Moors, in town to promote their film, "Blue Caprice.” (Bill O'Leary/Washington Post)

The first serious movie about the Washington sniper attacks isn’t really a movie about the sniper attacks. It’s about the man and the teenager who committed them and a vision of how they became the monsters who terrorized the region for 23 terrible days in the fall of 2002.

In “Blue Caprice,” director Alexandre Moors’s striking debut, John Allen Muhammad and Lee Boyd Malvo don’t even arrive in Washington until roughly 70 minutes into a 93-minute film, and then the violence is almost entirely off-camera. Neither are they “Muhammad” and “Malvo,” the names burned into local memory. They’re “John” and “Lee.”

It’s an uncomfortable bit of intimacy. John was executed in 2009, and Lee (See? It’s weird.) is serving a life sentence without parole in a Virginia maximum-security prison. When last heard from, he was spending 23 hours a day in solitary for his role in the shooting deaths of at least 10 people (probably more) and critically injuring several others, all by the time he was 17.

For Moors, a Parisian living in Brooklyn, the film is a small, intimate character study. It is not, in any way, a re-creation of the sniper attacks as popcorn thriller. Howard University theater major Isaiah Washington is mesmerizing as Muhammad, and Tequan Richmond (“Everybody Hates Chris”) is an almost non-verbal Malvo.

“It’s not any kind of reenactment or a biopic,” Moors says, sipping mint tea in the restaurant of the Ritz-Carlton Hotel in Georgetown on a recent afternoon. Thin, hair casually unkempt, he’s leaning back in his chair, explaining that the sniper episode had faded from his memory, and he only happened to stumble across old news reports while searching for a quick film project. This is relayed in his distinct Gallic accent, with pauses while he searches for the right word in English.

“It struck me, when I rediscovered this story, that it was a story of a father and son who were not actually father and son, but through sort of an adoption,” he says. “I thought that dynamic of those two characters was a great entry point to make a film about the culture of violence in America . . . and have a father teaching his son about life, and in this case ultimately grooming him to become a killer, a murderer.”

About this time, his star, Washington, breezes up to the table. He’s uptempo and jazzed, asking the waiter for some shrimp, adjusting his black-frame glasses, leaning forward, expounding as much as talking. “Blue Caprice” is his first notable role since his 2007 dismissal from “Grey’s Anatomy” (in the uproar that followed his using a gay slur), and he clearly relishes the chance to get back on film.

The 24-day shoot, mostly in Long Island (doubling for a rainy Tacoma, Wash., where most of the film is set), took place in September 2011. Washington was hired via a Facebook conversation only a few months earlier (“I had lost everything,” he says, after his firing and subsequent career nose-dive), and when he blew onto the set, he had to descend into playing a man with a disintegrating psyche, who says things like, “It’s not crazy to kill people.” He ties a terrified Malvo to a tree in the woods and leaves him there screaming, “Dad! Dad! Dad!” Day by day, he dominates the boy. It was not a pleasant experience.

“It was a dark place to be in,” Washington says. “He knew what he was doing to that kid. . . . It’s probably the most challenging role I’ve ever done.”

Moors, nodding, says that he “made a point of not being too prepared,” and though they were following R.F.I. Porto’s script, they left plenty of room for improv.

While stuck on set one day, looking for an outdoor location, they were in the rundown house they were using as Muhammad and Malvo’s temporary Tacoma residence. Killing time, Washington wandered down to the basement. It was dark, dank, fetid, nasty — and the pair came up with a chilling scene.

In the film, the owner of the home, Muhammad’s Army buddy, Ray (Tim Blake Nelson), is arguing with his wife. She wants Muhammad and Malvo, their guests, to get out of the house for good. There is a repeated thumping noise in the background. Ray goes downstairs, to the dark basement. There is Muhammad, ear muffs on, firing his Bushmaster assault rifle, over and over again, at a target.

What, Ray says, are you doing?

Muhammad stops firing and looks at him. “Just thinking,” he says.

It’s a great line — though completely fictional.

In reality, Muhammad did have an Army buddy, Robert Holmes, who let him stay at his house every now and again. But Holmes is black, not white, and there was no wife on the premises. The times that Holmes actually saw Muhammad fire the Bushmaster, it was at a backyard tree stump.

Still, for a movie that’s not worried about sticking too close to the facts, “Caprice” pretty closely follows the actual tragedy.

The portrayal of the first killing in the film is almost entirely accurate.

Muhammad, enraged at Isa Nichols, a friend of his ex-wife who testified against him at a custody hearing, sends Malvo to kill her. But the teen gunman is so nervous that when the door to the house opens, he shoots the first person he sees — the intended target’s niece, 21-year-old Keenya Cook. That’s pretty much the reality.

The second killing blends fact and fiction.

In “Caprice,” Malvo is dispatched to kill and rob a bar owner in Tacoma, netting the cash that allows them to buy the iconic car and set off cross-country to the D.C. suburbs, where Muhammad has tracked down his ex-wife and children.

In reality, while his ex, Mildred, had indeed relocated to the D.C. suburbs, the pair took a meandering cross-country trip in a different vehicle. The actual restaurant owner Malvo shot was Paul LaRuffa, who ran a pizza place in Clinton. LaRuffa had just closed up and was getting in his car on Sept. 5, 2002, when Malvo shot him. Malvo grabbed a briefcase from the back seat filled with about $3,500 and took off. LaRuffa survived.

They were seen a few days after that in the Trenton, N.J., area, and on Sept. 10, Muhammad bought the battered Caprice for $250 from Sure Shot Auto Sales. They were linked to shootings in Georgia, Alabama and Louisiana later that month.

The D.C. sniper shootings began on Oct. 2.

In the film, the shootings take place off-camera, although there is a montage of lone bodies at gas stations or parking lots. Some of those are generically accurate — many of the shootings did take place at such locations — but they are not mentioned as specific incidents.

The only one shown in detail — the shooting of a man in the parking lot of a sporting goods store in Fredericksburg — does not match any actual incident.

Lastly, on film, the pair are caught by chance.

Sleeping in the Caprice at a rest stop one night, there is a tap on the window. A cop warns them that they can’t park in the lot overnight and starts to leave — but then notices the curious hole cut in the trunk for the sniper rifle, and calls for backup.

In reality, police had identified Muhammad as their suspect, and publicly issued an alert for the vehicle. Hours later, not long after midnight on Oct. 24, a Pennsylvania refrigerator mechanic named Whitney Donahue pulled into a rest stop in Myersville, Md., on I-70 and saw the car. He reported it, then police sealed off the lot and swooped in.

For the star and director, all that was an afterthought: “Caprice” is what happened before, not during or after, the shootings.

“I wasn’t trying to portray [Muhammad] in a sympathetic way, but we’re talking about human beings,” says Moors. The idea is to “understand these people before they turn into monsters — that they are cousins and nephews and people at a backyard party.”

Blue Caprice

(93 minutes, at AFI Silver Theatre and West End Cinema) is rated R for disturbing violent content, profanity and brief drug use.