Is Bach playing? Look out!

But Kristi Brown, a musicologist at the Colburn School of the Performing Arts in downtown Los Angeles, says the music of J.S. Bach often works differently. These days, when you hear Bach in a film, he tends to accompany serial killers, Nazis and mad scientists. One of an emerging group of scholars who study classical music's resonance in pop culture, Brown is looking at how movies borrow Bach's music for scenes of stabbings, flayings and falling bombs.

What intrigues her is the peek the movies offer into the contemporary American unconscious, into the way mass culture understands, or misunderstands, high culture. The pop associations, she says, are an important part of the music's meaning, even if the composer never intended his music to work this way.

"I became interested in the films that were violent and that had a certain kind of protagonist," says Brown, 39, a daughter of the Central Valley who's surely among the nation's perkiest musicologists. These protagonists, she says, tend toward geniuses driven mad by technology and rationalism, or exemplars of a decadent European culture who've had the morality burned out of them -- from Benson, the crazed computer scientist in "The Terminal Man" (1974), to the erudite and malevolent Hannibal Lecter of "The Silence of the Lambs" (1991) and "Hannibal" (2001). Both men gruesomely kill, she points out, while playing the same piece, the 25th of Bach's "Goldberg Variations."

Other homicidal Bach lovers include the brilliant, shape-shifting title character in "The Talented Mr. Ripley" (1999), who plays jazz to impress friends but favors "The Italian Concerto" when alone; the Nazis in "Schindler's List" (1993), who pause to play a Bach piano suite on their way to ransack a Jewish ghetto; and the brainy, technologically savvy serial killer in "Kiss the Girls" (1997), who gives a victim menacing advice on how to play Bach on the violin.