The great James Caan classes up and adds a modicum of mystery to “The Good Neighbor,” a teens-torment-the-wrong-old-man thriller in the “Don’t Breathe” vein.

Or rather, that’s how it’s pitched. And had the filmmakers seen “Don’t Breathe” early enough, there would have been head-slapping and rewrites, tweaking and the like, to make this one work.

Because what they deliver is a drawn-out “surveillance” story, with a couple of tech savvy teenagers using hidden cameras to both watch every move of the “creepy psycho hermit” who lives next door.

But as “an experiment in perception,” smart-mouthed Ethan (Logan Miller of “Scout’s Guide to the Zombie Apocalypse”) wants to rig Old Man Grainey’s house so that the geezer thinks it’s haunted. And rich MIT-bound tech nerd Sean (Keir Gilchrist of “It Follows”) is just the guy to make this experiment come off.

They wire the old man’s house, switch on their monitors and giggle over Grainey’s reactions to thumps, power outages and a screen door that slams and clatters on a windless night, all by itself. They marvel at their power over him.

“It’s kind of beautiful, watching an old man sleep, wondering what he’s dreaming about.”

“World War I?”

Yeah, he’s going to MIT.

They wonder what’s behind that padlocked basement door. They call the cops, to rattle him. And they can’t figure out why this rude, mean old recluse “never once seemed afraid” of their every gimmick.

“Good Neighbor,” previously titled “The Waiting,” outstays its welcome, drifting on long after its climax. And the script forces an after-the-fact courtroom trial covered in flash-forwards into the structure, which art director turned director Kasra Farahani clumsily tries to disguise and integrate into the story without spoiling the suspense.

He fails.

Still, the kids are sharp, realistic and walk a fine line between unlikable and sympathetic.

And Caan plays this old man with a cagey resignation and menace. We do the math and try to figure out the possibilities. Is he keeping someone — perhaps his long-unseen wife — locked up downstairs? Did he kill her? Is he unafraid of the haunting because of guilt, or because he’s been haunted so long it rolls off his back?

The resolution would have had far more bite, suspense and satisfaction without the courtroom scenes. More moments were needed to establish Grainey as a realistic threat (again, see “Don’t Breathe”).

And a LOT less was needed after the climax, after the story has thrown its best punch.

Landing a lead like Caan underscores the fact that there was the germ of a twisty, tough thriller here. It’s too bad the script and uncertain direction let “The Good Neighbor” down.

MPAA Rating: unrated, violence, profanity, teen drinking

Cast: James Caan, Logan Miller, Keir Gilchrist, Laura Innes, Mindy Sterling
Credits: Directed by Kasra Farahani, script by Mark Bianculli, Jeff Richard. A Vertical Entertainment release.

Running time: 1:36