Jake Gyllenhaal has done a lot of good interesting work over the years. Now he’s turned in what I would call a virtuoso performance, playing a very disturbing and unappealing character, Louis Bloom, in Nightcrawler, written and directed by David Gilroy.

We first meet Lou Bloom stealing copper wire from a warehouse and slugging the security guard who tries to stop him. A revealing scene of him asking for a job after selling the wire to the manager of a garage showcases his glib, over-earnest recital of strengths obviously learned from motivational sales material of some sort. With his wiry build and his intense bulging eyes, Bloom is a strange and repellent person, and it becomes clear right away that he’s desperate to get ahead in any kind of job he can find. There isn’t much more backstory than that, except that he’s a loner living in a shabby little apartment in north L.A., obsessively studying the internet for methods of success and quick cash. By chance he stops to look at a car crash and notices a video photographer shooting at the scene, getting close-ups of the emergency crew that is working to get a woman out of the burning vehicle. The photographer is a stringer, slang for someone who takes footage of news stories and then sells them to the local TV stations for a bargained fee.

Bloom decides to try his hand at this, buying a video camera and slowly learning how to use it. His aggressiveness alienates the cops and EMTs that he encounters, but he has no scruples, and that makes him willing to go further than anyone else to get footage. After a shaky start, he manages to gain someone’s interest in his work—Nina, a news manager at one of the lower rated local stations, played by Rene Russo. His obvious amateur status and creepy demeanor makes her want to keep him at arm’s length, but he senses a possible opening—a similarity of character that gradually becomes more evident. Gilroy offers a dark critique here of the state of television news, with its reliance on crime stories and sensationalism over stories of more substance that don’t get the ratings. And as Bloom goes farther and farther over the line in his quest for the best and bloodiest news footage, the film’s dramatic pressure builds.

Along the way Bloom hires a hapless assistant named Rick, played by Riz Ahmed, who only wants a job and is bewildered by his boss’s aggressive motivational techniques. Sometimes the picture is quite funny, in a gallows humor sort of way, as Bloom’s attempts to manipulate Rick and Nina get more and more brazen, to the point where you almost gasp at his sheer nerve. Gyllenhaal creates and inhabits a character that is absolutely compelling and bizarre—it’s sensational work. And if you’ve forgotten what a real thriller is like—not the junk that usually goes by that name nowadays with the over-the-top action and special effects in which nothing is at stake because nothing seems real—well, the last forty minutes or so of Nightcrawler is as tense and gripping as they come.