One brow arched, the villain eyes his helpless victim with disdain. He lights up a smoke and slowly circles his nemesis, relishing the moment. He pauses to exhale and then tosses the cigarette to the ground, crushing it under his ominous black boot as if it were his enemy.

Scenes such as this one are found in countless Hollywood movies. From the menacing bad guy to the sexy leading lady, many actors depend on smoking to convey a certain attitude or persona. But research indicates that tobacco's starring role in the movies may be building up to a dangerous plot twist for American teens.

The Centers for Disease Control and Prevention recently announced that decades of progress in reducing tobacco presence in movies were brought to a screeching halt in the mid-'90s. By 2002, the levels of tobacco use onscreen had once again skyrocketed to those not seen since 1950 -- a period in which cigarettes were so pervasive on film, they should've been billed in the credits.

Research presented at the World Conference on Tobacco or Health in Washington, D.C., further proves that smoking is once again taking center stage in Hollywood. Of the 100 top-grossing films between 1996 and 2004, 90 percent of R-rated films featured tobacco, according to a report by the American Legacy Foundation in collaboration with Dartmouth Medical School.

Even more shocking: Seventy percent of the examined youth films (those with a G, PG or PG-13 rating) also included tobacco, the study said.

Fueled by economic factors, the Motion Picture Association of America has "down-rated" movies in recent years, according to the research. Because PG-13-rated movies typically gross more than R-rated ones, films that would have formerly warranted an R are now stamped with a PG-13, the study said. The result is that more questionable content, including tobacco imagery, seeps into teen-oriented flicks.

"This news is a wake-up call to public-health officials and other leaders," Dr. Cheryl Healton, president and CEO of the American Legacy Foundation, said in a statement. "We have seen a downward 'ratings creep,' in which studios are shifting depictions of smoking into teen-rated films, and research continues to prove the link between young people seeing smoking in movies and starting to smoke."

This visible link is exemplified in the groups' past research, which concluded that 38 percent of youth-smoking initiation can be traced to onscreen smoking.

"Films influence children to smoke because it's a tremendously powerful emotional medium and the presentation of smoking in movies effectively functions as subliminal advertising," said Stanton Glantz, a professor of medicine at the University of California, San Francisco, and founder of the Smoke Free Movies project.

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As is the case with all effective subliminal advertising, susceptible children are reaching for the cancer-causing sticks in droves without thinking about the consequences. And why shouldn't they? After all, it's not often that Hollywood shows a central character who smokes later dying of lung cancer or emphysema.

"Thank You for Smoking," released earlier this year, satirized the mutually beneficial relationship that allegedly goes on behind closed doors between Hollywood and Big Tobacco. But buried beneath the tongue-in-cheek dialogue lay a real message about the two formidable forces: "There is a long-standing relationship between the tobacco industry and the film industry that goes back decades," Glantz said.

In 1999, major tobacco companies in the U.S. vowed in a legally binding document to Congress to cease paying for product placement in movies. Yet, since the agreement, more than 40 billion "tobacco impressions" have found their way on film, according to the American Legacy Foundation study.

So then, how are tobacco products still butting into Hollywood movies? Glantz speculates that money and other questionable business deals may still occur. The main method, however, is finding a loophole.

A press release issued by Philip Morris USA in March states, "Although some continue to believe that the appearance of cigarette brands and brand imagery in movies and television shows is the result of product placement by tobacco companies, Philip Morris USA continues to deny all product-placement requests for its brands."

Philip Morris USA may not partake in product placement -- but Philip Morris International might, according to Glantz. Philip Morris International is not bound to the 1999 agreement and is free to offer money in exchange for product screen time, Glantz said.

In response to Big Tobacco's persistent presence in movies, many organizations are striving to put stricter policies in place regarding smoking. But while few people publicly praise the use of tobacco imagery on the big screen, just as few seem to vocally denounce it. Advocates note that the key is a proactive approach by audiences and studios alike.

"There are people who are individually doing the right thing, but one of the great disappointments we've had is that no one in Hollywood has come forward to take a leadership position on this," Glantz said. "[Famous] people have been willing to work with me quietly and secretly, but no one has been willing to publicly oppose smoking in film."

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