“Ed Kemper” is a serial killer portrait that’s as pitiless as it is artless.

This feature film, no doubt inspired by Netflix’s “Mindhunter” series bringing attention to the “other” notorious mass murderer named “Ed” (“The Butcher of Plainfield” Ed Gein inspired “Texas Chainsaw Massacre,” etc.), it’s a simple “How he went about it” account of Edmund Kemper’s crimes attached to simplistic “Mommy made him do it” psychology.

There’s no suspense. We don’t see the California police missing early ’70s clues or closing in on their quarry, because they didn’t.

The plainly fortyish Brandon Kirk is meant to play the hulking Kemper — he’s six foot 9 and still in prison — who was 24-25 when killed female hitchhikers around Santa Cruz in the early ’70s. Kirk is joined by the worst John Wayne impersonator you ever saw (for delusional manhood lectures) and a teenage girl (McKenna Ferry) cast to play “Eddie” as an unbalanced child locked in the basement with Satan (in his nightmares) during the kid’s cat-torturing childhood.

If you mutter “WTF” at that last stunt, you’re not being gender phobic. There’s absolutely no resemblence between her, teen Kemper (Benjamin Philip) or adult Kemper.

Susan Priver plays Clarnell, the hippy-hating failed actress harridan who raised Kemper, a three-times-married hard-drinker and generally twisted sister who is presented as the “cause” with 10 dead victims as the”effect” in the film’s telling.

“Hey, Mom,” teenaged Edmund says when he calls her after shooting and stabbing his paternal grandparents. “I hope you’re happy now.”

The “monster” was hospitalized for killing his grandparents as a teen, and was released by an out-of-its-depth prison mental health establishment only to slaughter others as an adult. That makes mental health workers sort of secondary villains, here.

Ed is lectured by the “You’re going to be fine, just fine” shrink leading him out of Atascadero State Hospital as he’s released five years later to “stay away from your mother.” Naturally, he moves in with her because he has nowhere else to go.

A job as construction crew flagman for the state highway department supports him, and his mother’s insults and jabs drive him as he takes note of hitchhikers and plots what he’d like to do to them.

As his name rings a bell with a workmate, Ed admits that he’s the same guy who killed those two people up in North Folk a few years back.

“I just wanted to see what it felt like to kill grandma!”

Director and co-writer Chad Perrin is mainly interested in the MO of the heartless murders, and in the perversion that Kemper inflicted on the corpses.

Whatever lip service Kemper pays to his lack of remorse and those he “hurt” — who don’t include the people he admits he “slaughtered — doesn’t lend insight to his broken thinking or ways we might recognize his “type” in others.

Tip to parents, far and wide. If they abuse animals, they’re going to hurt people. And that’s not exactly a secret.

As this isn’t a fictional horror film, where violence is but a challenge, and often a jokey “creative outlet” for genre filmmakers, I found “Ed Kemper” grim going, and nothing more. Insights into a sick psycho’s psychology? Not really. Entertainment value? Nope. None at all.

Rating: unrated, graphic violence, sexual content, profanity

Cast: Brandon Kirk, Susan Priver, Benjamin Philip, McKenna Ferry and Brinke Stevens.

Credits: Directed by Chad Ferrin, scripted by Chad Ferrin and Stephen Johnston. An Epic/Dread release.

Running time: 1:31