There's something foreboding about the initial Codey Steele-Vanna Bardot nighttime backseat fuck scene that starts A Killer on the Loose: too dark, too tentative, too quiet, too slow, too ... something. Crickets chirp, cars vroom by on a nearby road, the suspense builds. Is that view of the obliviously fucking couple through the open hatchback door a POV shot? The scene concludes, Bardot steps away, stops a few feet in front of the car to take a quick leak—and is abducted by a guy in a passing car.

The next morning, jaded veteran supervisor Stirling Cooper puts eager newbie Aiden Ashley on the missing-girl case, possibly connected with an active serial killer investigation. When Ashley wants to pick the brain of an expert, Cooper is dismissive: "What makes you think The Professor will even talk to a little girl like you?"

Meanwhile, the kidnapper quietly sharpens a knife as Bardot pounds on the door holding her captive. When Ashley asks The Professor—Seth Gamble, in an orange jumpsuit, locked in a dungeon-like prison cell—for help, he quietly asks, "Do you think I had anything to do with this?" Gamble offers to help, playing cat-and-mouse games with Ashley—whose "I can handle this" reassurance to a nearby guard is not reassuring at all. 

A hint from Gamble about "revenge porn" sends Ashley to the internet where she finds that Steele is the perhaps-unwitting wingman for the killer, with DNA connections with all the previous murder victims and a recent online hookup with Bardot. When Ashley tries to pry more info from Gamble, he asks her, "Do you like sucking dick?" She ups the ante by getting on her knees and contemptuously goading him, so Gamble turns the tables and tells her to blow the guard (Dante Colle) who's been watching them—and then, sending her to see his "friend" as the guard's jizz dribbles down her chin. "I think he'll have the information you need," Gamble says.

That night, Ashley goes to the friend's place, slipping off her bra before she knocks on his door. The "friend" is Colle. Neither of them know why Gamble sent her there, but he apologizes for their encounter earlier and she says it's okay, nobody was forcing her, and advises him, "Next time, try to say your name before you put your dick in someone's mouth." A sudden cutaway in the sex scene that follows shows that Colle is recording the encounter on a spycam, being watched in real time by Gamble in his cell. 

Back at the cell, Ashley admits to Gamble that she was thinking of him during yesterday's blowjob. Gamble makes Ashley an offer: Get me moved to another facility, I'll tell you where Bardot is. But during the transfer, Gamble kills the supervising officer and, freed from his cell, presses his advantage with Ashley in a hard, rough scene before he gives up the identity of the serial killer: Colle. "He's easily pushed in the right direction, as long as you know how," he tells Ashley, right before handcuffing her to his cell and escaping. The loose ends get tied up and the final fadeout has Gamble walking on the beach, laughing as the waves reach his feet. 

Director Greenwood handles his own script (a mix of familiar and new elements, written with Maddy Barton) with just the right mix of dread and suspense. Gamble inhabits the creepy Hannibal Lecter part, dominating the frame as well as the naïve Ashley character. Kudos to Buddy Light for the masterful dark-on-dark evolving into bright daylight cinematography.