They spend their nights like famished coyotes, hunting fresh meat. "If it bleeds, it leads," as one character in "Nightcrawler" says, summarizing the link between gore and breaking TV news.

Starring Jake Gyllenhaal, the film's title comes from the nickname given to the kind of freelance video journalists who shoot bloody traffic accidents to sell to local TV stations.

The Oscar-nominated star plays Lou Bloom, a jobless and hungry Angeleno who turns to nocturnal body-chasing across Los Angeles to survive. He lost 10 kilos for the film, released on Friday in the United States.

Gyllenhaal said he and director Dan Gilroy "talked a lot about coyotes .. in Los Angeles particularly at night, the wild animals that come down (from the hills) and are kind of surviving, even though the metropolis has taken over."

"He's a coyote. He's hungry," said the actor, nominated for an Academy Award for 2005's "Brokeback Mountain."

One cut scene had Bloom ordering a cheeseburger to eat in a fast-food restaurant, then deciding to take it out because it was 99 cents cheaper.

"This is a guy who doesn't eat much," said the 33-year-old blue-eyed actor, who is more used to being on the other side of the paparazzi camera's lens.

The thriller, which sometimes comically satirizes our voyeuristic society, sees Gyllenhaal's character slowly transform into a psychopath risking his own life and others' to shoot video with no apparent empathy, or instinct to help those he is filming.

"It is supposed to be the journalist's responsibility to capture the story, to feed the audience .. no matter what. And he's doing nothing really that can be called illegal," said the actor.

"He didn't commit the murders, he's innocent. But is he?" he asked.

A screaming woman

Bloom is pushed to go ever further in his morbid journalistic race by Nina (played by Rene Russo), the TV producer he is working for, who wants the goriest possible footage.

"Think of our newscast as a screaming woman running down the street with her throat cut," she tells him at one point in the movie.

Bloom gradually advances in his new career, sprinkling his conversation with management speak like: "I work hard and I set myself high objectives" and "to win the lottery you first have to earn the ticket."

"You'll see that this is a job I happen to be good at," he adds.

Blackmail, lies, manipulation: for Bloom, the end justifies the means, and the only limit the TV station's producers give him is not moral, but whether they will face legal action.

Gilroy, who also wrote the screenplay and is making his directorial debut, sees his anti-hero as someone who has been abandoned and abused when he was younger.

"Lou has no empathy ... a part of Lou has shut down," he told reporters, presenting the film before its release.

"I think what he does is less bad than a CEO who takes pension funds from people and builds a yacht and gets on the cover of Business Week for this, and celebrated for this," he said.

"It's a brutal world we live in, and Lou sees it as it is ... a world where what matters most is the bottom line," he added. "I believe if you come back 10 years after the end of the movie, he will be running a major network."