Parental paranoia gets a boost from the quietly nasty “Emelie,” where the cool new baby sitter (Sarah Bolger) turns out to be a full-on psychopath. This is not a spoiler; the film begins by telegraphing impending doom (and wraps up, underwhelmingly, with thriller clichés).

But couple Dan (Chris Beetem) and Joyce (Susan Pourfar) only know they’ve lucked into a last-minute replacement for their sick regular sitter; the kids — especially 11-year-old Jacob (Joshua Rush) — are initially dazzled by her disregard for the rules.

By the time she feeds the family hamster to Jacob’s python, the kids realize too late that all is not right — and how. Director Michael Thelin, in his feature debut, has an undeniable knack for making an audience squirm without resorting to excessive gore or jump scares. Still, I’m not sure I ever needed to see the faces of young children watching their parents’ (unseen) sex tape.