Life sometimes has a disturbing habit of mimicking art.

Charles Manson's followers scrawled the name of a Beatles song, "Helter Skelter," on the walls of a house owned by one of their victims. The shootings at a school in West Paducah, Ky., in 1997 allegedly were inspired by a scene from a Leonardo DiCaprio movie, "The Basketball Diaries." A 1994 murder in Texas bore disturbing similarities to events depicted in Oliver Stone's "Natural Born Killers."

And now -- maybe it's just a coincidence -- there are echoes of an old movie in a new crime.

The movie, "Malice," is a psychological thriller released in 1993 and starring Alec Baldwin. "You ask me if I have a God complex?" Baldwin's character, a surgeon, says when challenged during a legal deposition. He pauses dramatically before declaring, "Let me tell you something: I am God!"

I am God. The same three-word declaration of psychopathic egomania appears on a tarot card found Monday by police at the scene of the sniper shooting in Bowie. It could be a quirk, unrelated to a forgettable film, but for this disturbing fact: "Malice" aired on the TBS cable network last Thursday evening, only four days before the tarot card turned up in the woods outside a Bowie middle school.

Related or not, the killer's brazen means of communication puts a chilling real-world spin on an ancient device in fiction, the "signature," a distinctive mark left by a character to announce some misdeed or just his presence. It's his taunt, his boast, his brand.

The discovery of the card recalls the signature of a fictional sniper in James Patterson and Andrew Gross's recent best-selling thriller, "Second Chance." In that story, the most striking clue in the murder of a girl outside a church is a calling card in the shape of a mythical monster called a chimera.

Signatures pop up in popular art high and low. It's the Riddler's question mark, left behind to rile Batman. It's the playing card that Lt. Col. Bill Kilgore (Robert Duvall) leaves on the bodies of Viet Cong killed by his air raids in "Apocalypse Now."

It's the fish sent to the Corleones by Luca Brasi's assassins in "The Godfather" -- the visual realization of the notion that Brasi would henceforth be "sleeping with the fishes." It's the horse head in the bed.

And it's sick, of course, when the stuff of dreams and nightmares transmogrifies into reality.

"It's kind of a creepy phenomenon of modern life [for a criminal] to blur the line of the fictional," says Maureen Corrigan, who teaches a course in detective fiction at Georgetown University and reviews such books for NPR and The Post. "I've read that scene a thousand times where the killer leaves a playing card on the body, usually the ace of spades. This guy is following that same pattern."

The signature has, of course, been real before. The burning crosses and white hoods of the Ku Klux Klan were portents of terror in the post-Civil War South and Midwest. The Black Hand was the symbol and name for a terroristic secret society that was associated with the Mafia. It was especially active in New York City in the late 19th and early 20th century. According to the Columbia Encyclopedia, as much as 90 percent of New York's Italian population was blackmailed by letters threatening death and marked with a black hand.

In more recent times, attention-craving serial killers have "marked" their crimes with letters to authorities or even the news media. David Berkowitz, the Son of Sam, more or less corresponded with New York newspaper columnist Jimmy Breslin in 1976 and 1977 before being brought to justice. The Zodiac Killer -- so called because his crimes occurred in close proximity to a solstice or equinox -- mailed as many 20 letters to news media in California between 1966 and 1981, claiming "credit" for various murders (the letters contained intimate knowledge of events, and thus were considered authentic by investigators). The Zodiac Killer was never apprehended.

But the "signature" isn't always sinister. Good guys use it, too. Think of the Lone Ranger's silver bullet, or Zorro slashing a "Z" on the imperialists. The TV hero Paladin, who dispensed his own brand of frontier justice, had a business card adorned with a chess piece that read "Have Gun Will Travel."

Think, too, of the Scarlet Pimpernel, who saved the innocent from the guillotine and memorialized his good deeds with . . . a scarlet pimpernel (a reddish flower).

"My first reaction when I picked up the paper this morning was that this guy has been reading too many bad novels, or watching too many lousy TV shows," says a local author, who writes best-selling suspense thrillers. "You don't often see a villain who acts like a Hollywood character."

The author, who asked not to be identified out of concern for himself and his family, says the sniper may be lifting a technique employed by all thrillers and works of suspense: leaving a clue for the hero (and the reader/viewer) to chase down. In this way, he would be creating a more tantalizing mystery -- precisely what creators of fiction strive for.

Reality following fiction? And someday perhaps fiction will follow this bad patch of reality. Can scriptwriters resist the notion of a murderous character who leaves tarot cards?

Not likely, answers the author. "The snake," he says, "has swallowed its tail."

Long before Zorros such as Antonio Banderas, far left, sliced their first Z's in the movies, the signature jumped from fiction into real life, the Ku Klux Klan and David Berkowitz, near left, providing particularly horrific examples.Alec Baldwin in 1993's "Malice": Did a cable TV repeat of the forgettable thriller inspire the sniper's taunt to police?