Police procedural meets torture porn in “Untraceable,” a melodrama that has cops and FBI agents tracking down a serial killer who’s disposing of people on a website that automatically offs the victims faster the more viewers log on. It comes from director Gregory Hoblit, who specializes in potboilers, sometimes excellent (“Primal Fear”) and sometimes mediocre (“Fracture”). Unfortunately, this is one of his weakest efforts, sleazy and absurd rather than clever and surprising.

The picture focuses on Jennifer Marsh (Diane Lane), a single mom and federal shamus who tracks down cybercriminals on her trusty computer in tandem with her colleague Griffin Dowd (Colin Hanks). The duo latches onto to a new, untraceable site whose mysterious, sinister controller—one of those masterminds who seems to have unlimited funds at his disposal, as well as a good deal of chutzpah—first tortures a stolen kitten to death and then moves up the ladder to a human being, an unhappy fellow named Herbert Miller (Tim De Zarn), who bleeds to death in a contraption devised by the criminal to speed up the process at a rate that’s accelerated as the number of watchers increases. Not only do other victims follow—one of them a person close to Jennifer—all killed in increasingly bizarre ways involving heat lamps and sulfuric acid but at a speed always dependent on the number of hits, but the killer even threatens the Marsh family itself, including Jennifer’s adorable young daughter Annie (Perla Haney-Jardine). The cad!

There’s more than a touch of “Saw” and “Hostel” to the killer’s Rube Goldberg-style torture machines, which is tawdry enough for a picture of this sort, but what really derails “Untraceable” is the fact that ultimately the means of deciphering the killer’s identity is less clever than what you’ll encounter in the average episode of a television program like “CSI” or “Criminal Minds.” To add to the sorry state of affairs, the face of the culprit is revealed too soon, the child-endangerment subplot is cheap, and the last twenty minutes of the picture, with a damsel-in-distress turn, is repugnant. The worst aspect of the script, though, is the motive ascribed to the villain, which—as far as I can understand it—involves protesting against violence on the Internet by taking violence on the Internet to a new level. That idiotic premise is the cinematic equivalent of having your cake and eating it too: it allows the filmmakers to load up the picture with torture scenes while simultaneously deploring their prevalence in pop culture.

Nor is “Untraceable” particularly well made. Hoblit lets things drag too much, and the leisurely pace makes the plot holes all too evident. And while Lane works hard to look concerned and intense, furrowing her brow and staring at the floor (as well as her computer screen), she never manages to convince you that Jennifer isn’t slightly dull-witted (especially in the last reel, when her actions appear to invite disaster), and Hanks is affable but not much more. (There’s a big gap in the subplot involving him, moreover, that is a real cheat.) Even worse is the colorless Billy Burke, who’s essentially reprising his role from “Fracture” as a dedicated cop. Mary Beth Burt shows up as Jennifer’s mother, and is surprisingly bland, while little Haney-Jardine fails to charm. Erstwhile child star Joseph Cross (he was the lead in both M. Night Shyamalan’s “Wide Awake” and the dreadful “Jack Frost”), meanwhile, fails to raise goosebumps as the malevolent webmaster. On the technical side, Anastos Michos’ cinematography catches the Portland atmosphere well, but moodiness isn’t enough; and Christopher Young’s score is unremarkable.

“Untraceable” obviously wants to emulate the effect of “Se7en,” but it’s a runty imitation. On the scale set by that David Fincher movie it barely merits a three.