At their least, the myriad serial-killer movies that followed in the imitative wake of “Se7en” three decades ago have gotten the grisly part down, but find compelling suspense, atmospherics and original narrative ideas harder to come by. Such is certainly the case with “Damaged,” which serves up a considerable number of victims’ severed limbs, yet is likely to leave scant impression — scarring or otherwise — on the viewer. 

Though Samuel L. Jackson and Vincent Cassel are top-billed, Gianni Capaldi (who also co-wrote and produced) is essentially the lead here as an Edinburgh detective on the trail of a murderer whose crimes appear to extend those of a Chicago perp six years prior. There’s a similar lopsidedness to the character dynamics, as the convoluted story sometimes seems to dole out emphasis more for reasons of marquee value than narrative logic. Directed with polished competence by TV episodic veteran Terry McDonough, this watchable but forgettable thriller runs a brisk gamut from the uninspired to the implausible. Lionsgate is releasing it to U.S. theaters as well as digital and on-demand platforms April 12.

At the start, a young Scottish woman opening her door to an alleged delivery person is mortally attacked. The gruesome condition in which her remains are discovered — extremities arranged in an “inverted cross,” other Satanic symbols, entire torso missing — distinctly echoes that of five people previously slain in Chicago, their killer never found. When a second woman meets the same fate, local investigators Boyd (Capaldi) and Kessler (Kate Dickie) get joined by Yank cop Lawson (Jackson), who had worked on those now-cold cases. He also calls in former colleague Bravo (Vincent Cassel), who’s conveniently moved to the U.K. 

At first, suspicion falls on a surly neighbor (Brian McCardie) known to have quarreled with the first new victim. Then focus shifts to McGregor (John Hannah), an even more unpleasant character recently kicked out of an already extreme (if ill-defined) religious sect for being “too radical.” Others also spark distrust, including some of the investigators themselves — and it probably doesn’t help that Lawson is an unapologetically sloppy drunk, his behavior explained by mourning for the wife who was among the original casualties. 

Koji Steven Sakai, Capaldi and Paul Aniello’s script feels like an awkward compromise between competing visions, as well as somewhat inorganic multinational casting. While his performance is okay, frequently surrendering focus to better-known actors doesn’t lend Capaldi’s character enough heft or personality to center the film, as it seems meant to. Jackson is in enjoyably playful form at first, though later he’s saddled with more credulity-straining narrative baggage than he bothers to treat seriously. Cassel and particularly Dickie are underutilized, while the preliminary villains make a menacing impression the screenplay fails to flesh out much. (Even the story’s religious angles turn out to be a red herring.) Suspense is minimal in part because the murder victims are mostly only introduced to be offed — the film is less interested in their peril than lingering on the gory aftermaths. 

McDonough has directed a lot of quality series installments on both sides of the Atlantic over the last quarter-century, including “Better Call Saul,” “Breaking Bad” and “The Street.” This belated first theatrical feature gets the benefit of his slick professionalism, as well as that of his overqualified actors. But they can only do so much with material that feels cursorily sewn together from elements of prior, better genre exercises, and which finally collapses into explication-heavy twistiness that leaves any remaining believability behind. 

Nicely enough turned in all tech and design departments, “Damaged” is too efficiently handled to be dull, or even overtly bad — though viewers may find themselves rolling their eyes a bit after a while. But the overall lack of conviction reduces content that should be alarming and macabre to the status of an unmemorable time-killer.