You’re the mayor of New York. An anonymous British street artist has waged a month-long illegal exhibition on the streets of your fair city and you can’t get the NYPD to arrest him. What do you do?

This is the position Mayor Bloomberg finds himself in, after making a statement that Banksy’s stenciled work is “graffiti” — not art — and that Banksy should be arrested for ruining people’s property. However, a “high ranking NYPD official” told the Daily News that the department is not investigating the street artist since no complaints have been made by building owners.

Is the NYPD trying to lull the elusive artist into a sense of false security?

In order to constitute graffiti on private property, the law states that a person must have the intent to damage the property and do so without the express permission of the building owner. No complaints are needed to make an arrest for graffiti on city property. A prominent artist’s mark on a building’s wall doesn’t fit easily within the intent to damage element — not when that artist’s work sells for hundreds of thousands of dollars or more.

Graffiti artists have attempted to make this argument before, with little success. New York courts have held that whether someone actually causes damage is irrelevant for purposes of the charge of making graffiti, refusing to judge between art and vandalism. But they have never been confronted with a street artist whose mark unquestionably increases the value of a wall like Banksy’s does.

If Banksy’s pieces from his Better Out Than In exhibition can be preserved, they could fetch high price tags. According to Gallery owner Stephan Keszler, the Greenpoint “Plato” door alone could fetch between $20,000 and $40,000. Banksy walls sell for even more. Some building owners have realized this and are safeguarding the works.

The second element of the crime of graffiti — graffiti done without the express permission of the owner of the building — is easier to prove. NYPD has claimed that they cannot go after Banksy because no complaints were made, but this is simply not true. Maybe they have not read the statute: it is clear that Banksy has neither sought nor been granted the express permission to mark up anyone’s building.

Technically, all the police would have to do is ask the building owner whether they had given Banksy permission to mark the building and if the owner replies “no,” the element would be satisfied. Of course, the building owner can refuse to cooperate with the police–like what happened on Monday in the South Bronx–and the arrest would not be processed.

An argument over whether Banksy’s art constitutes graffiti under the law is one of those academic questions that have nothing to do with the police’s authority to arrest him. The police can arrest Banksy and he could be charged with misdemeanors punishable by up to one year in jail. If some patrol cops happened to catch Banksy in the act, they wouldn’t know they had nabbed a famous artist; he would be just another vandal. The police could rightfully infer that he had the intent to damage the property and that he did not have the owner’s permission.

The situation is a little less clear if the Vandal Squad was to go after Banksy. The Vandal Squad consists of graffiti experts who know the value of Banksy’s work. If someone plasters $20,000 worth of 24k gold on your wall, do they intend to damage the property or bestow a windfall? Maybe you don’t like the gold, sure it’s gaudy, but there is always someone who’ll pay good money to take that gold off your hands.

My advice to Banksy? Don’t get caught.

  The Law works within the New York City legal system.