Some movies don’t need to tell you they’re “based on a true story.” You don’t have to recall the dates and details. You don’t question what unfolds on the screen. Based on everything we’ve seen and heard over the past decade, you just know.

“The Killing of Kenneth Chamberlain” is a gripping, heart-breaking real-time account of a White Plains, New York police call that took just over an hour to go totally, irrevocably and inexcusably wrong. A Black man, a Marine Corps veteran with medical issues, was dead.

And since it was 2011, no charges were brought against the police, no jury would give legal satisfaction to his heirs. Because such stories didn’t fit into an unfolding national tragedy and nationwide policing scandal.

Veteran character actor Frankie Faison, an established screen presence long before the original “Coming to America,” before Spike Lee’s “Do the Right Thing” or Alan Parker’s “Mississippi Burning,” gets a rare leading role and acts the hell out of this spare, compact tragedy with just a handful of characters and a single setting.

He has the title role, a Marine Corps veteran with limited hearing, a bad heart and mental health issues. He takes his medic alert monitor off to get through a restless night. And that sets off a chain of events, a slow-motion disaster that plays out with a depressing inevitability that no amount of shouting at the screen can halt.

The medical monitoring company calls, and can’t wake him to answer the phone. It’s five AM. They call the police for a “welfare check” visit.

Three White Plains PD officers show up — a rookie (Enrico Natale) who used to be a middle school teacher, a hardcase Sgt. (Steve O’Connell) and a short-tempered veteran of the force (Ben Marten). They pound at the door, waking the groggy, hearing-impaired old man.

We fret for him as he slowly shuffles to the door, worry about his confusion at presence, and expect the worst from the guys in uniform. Because “I do not have an emergency…It was an accident. Thank you for your trouble” is not moving them from his apartment door.

As the pounding goes on, we see the impatience of the two older cops. And we’ve already heard the telltale signs that give away how this evening will end.

The neighborhood is “the third world.” The phrase “learn who’s boss” comes up. Racial slurs slip out. The nicest is “cocoa puff.”

And no “What’s going on here?” neighbors, no pleas from the alert company operator, who calls the police to call them off, no begging by the sick old man’s niece (Angela Peel) will get these officers to move on.

We hear the “Check his ID, run’em.” We see the escalations, sense the tension that rises with every “You are not coming into my house” and “You have no warrant, no probable cause.”

The die is cast long with the “We’re handling this” brush-offs of neighbors and family, before reinforcements arrive, before a fresh sergeant shows up with “irons” (battering rams) and a brusque order to “Have your guys tac up!”

Faison’s layered performance staggers from confused to paranoid, rational and outraged to rational and terrified. He doesn’t have to tell his son or sister by phone “You know how the police are around here.” They do.

Natale gets to play the reasonable, “Let’s just leave” rookie, the rational, educated man among hardened authority junkies. Their racism is almost immaterial. Their big beef is being told “no” and “you have no right.”

The rookie? He’s a “cry baby,” and “emotionally sensitive” and therefor must be ignored.

Writer-director David Midell cast this well, turned in a script with a bitter, metallic aftertase and never wastes a second of screen time, giving us two points of view — outside and inside that door — letting us stay one step ahead of this slow tumble off a cliff.

We experience the assault the way Kenneth did — his hearing aids roaring the noise, the rational fear that any time the police enter your home “they want to hurt me” irrationally amplified.

And in the closing credits, we hear the original medical alert calls and phone conversations and see snippets of the “raid” on old video.

Because sometimes “based on a true story” isn’t damning enough.

Rating: unrated, violence, profanity, racial slurs

Cast: Frankie Faison, Steve O’Connell, Enrico Natale, Ben Marten, Angela Peel and Tom McElroy.

Credits: Scripted and directed by David Midell. A Voltage film, a Gravitas Ventures release.

Running time: 1:21