A graffiti writer known as Poo at work in an abandoned warehouse in Long Island City, Queens. More Photos >

Ray looks like a police officer. But he's a graffiti writer, with a trim goatee and graying at the temples, who wears a stolen orange New York City Transit vest when sneaking into subway tunnels. He has a stolen set of keys that he says unlock subway cars, and he boasts that he has left his graffiti tag name, PRIZ, on subway cars at least 2,000 times in the past 20 years.

At 40, he says he has no plans to quit.

But if Lt. Steve Mona and the 75 other police officers who make up New York City's new antigraffiti unit have their way, Ray and other self-described "graffiti writers" will have no choice but to stop.

If Ray resembles a police officer, Lieutenant Mona, 45, looks like a biker. A hulking man with arms covered in colorful tattoos, he commands the 10-month-old unit, the Citywide Vandals Task Force, whose sole duty is to hunt down and arrest the thousands of people like Ray who illegally scribble, scratch, spray-paint or, using acid, burn writing onto public and private property.

Unlike Ray, who finds beauty in his work, Lieutenant Mona, an 18-year veteran of the transit police whose best friend as a teenager was a graffiti writer, has an uncompromising view: "I'm not an art critic, I'm a cop. I know what a crime is."

The debate over how to best eradicate graffiti has gone on for more than three decades. In January, Mayor Michael R. Bloomberg announced a sweeping plan to combat graffiti by merging the antivandalism unit of the Police Department with that of the transit police. Graffiti, the mayor said in his State of the City address, is "an invitation to criminal behavior."

The new squad is equipped with infrared and digital cameras, a database with thousands of tags and profiles of those arrested, and a book that contains the 100 or so "worst of the worst" repeat offenders. The police, Lieutenant Mona said, are intensifying their efforts.

But so is Ray. And so are others like him who are adapting to the crackdown. A dozen graffiti writers, who spoke on the condition that their full names not appear because what they do is a crime, said that tagging has become more about strategy than ever before.

They map out targets and plot escape routes. Many go out exclusively at night, favoring rooftops and boarded-up buildings that aren't likely to be painted over quickly, if at all. They trade tips online, and snap photographs of, or videotape, their work, rather than returning to admire it.

But they also admit to a new sense of paranoia. Because each side in the graffiti war keeps tabs on the other, writers are painfully aware that plainclothes officers are patrolling streets and subways, taking pictures of the hardest-hit sites, surfing graffiti Web sites, and dropping in on gatherings of writers and fans.

"When the 'goon squad' first started cracking down, a lot of people went out there with the attitude, 'We're going to get over tonight,' " Ray said. "So of course, they got caught."

Graffiti arrests are up 88.9 percent citywide since January, compared with the same period last year, according to police statistics, an increase that Lieutenant Mona attributes to his unit.

Despite the increased risk of arrest, for many graffiti writers the Citywide Vandals Task Force is not a deterrent so much as a "call to arms," said Eric Felisbret, 42, the editor of the graffiti Web site @149th Street. "It's a challenge," he said. "Most of these guys wouldn't be caught dead painting in a legal context. You get more charged up, and more prestige, this way."

For a younger graffiti writer like Harley, an East Village resident whose tag name is IMUNE, the new unit means nothing more than a shift in approach - better planning and riskier escapes that include jumping across rooftops while being chased by the police, which he brags about doing eight times.

Harley, 19, is a baby-faced skateboarder with sand-colored hair who began tagging six years ago. He said he had been arrested six times in three years - including twice this year. The longest he has spent in jail is 43 hours, he said, and he has been fined $200 twice. But he and his friends keep tagging illegally.

"A lot of my friends don't really care about the squad," said Harley. "But things definitely haven't been like they used to be."