PHILADELPHIA, Pennsylvania (AP) - Art theft may conjure up images of a suave movie villain creeping through a dark gallery - or last year's bold daylight robbery of Edvard Munch's "The Scream" from a Norway museum.
Most art heists, however, are far more subtle, involving forged documents, fake prints or smuggled cultural artifacts that slowly make their way into the hands of private owners or museums.
It's also a huge industry: Interpol ranks it third among property crimes worldwide.
A new FBI task force on stolen art hopes to learn more about the global trade - and how to tackle it - with the help of professionals and scholars in museums, as well as art and antiques dealers.
Worldwide, only 5 percent to 10 percent of artwork reported stolen is recovered, said Lynne Richardson, who manages the art theft program at FBI headquarters in Washington. The group wants to learn more about how purloined art makes its way to U.S. shores.
"We would like to identify more smuggling groups, and more organized crime groups that are involved in this," she said.
This week, the eight task force members visited curators at the Impressionist-rich Barnes Museum, conservationists at the Philadelphia Museum of Art and archaeologists at the University of Pennsylvania's Museum of Archaeology and Anthropology, as well as art and antiques dealers.
Most art stolen in the United States is taken during residential burglaries, the FBI said. But perhaps the bigger problem is the sale of art stolen offshore to eager U.S. buyers, who may or may not sense their illicit history.
"By the time they arrive here, they have (forged ownership) papers on them," Richardson said.
Although collectors can be prosecuted for buying art that they know - or should know - is stolen, that rarely happens.
More often, prosecutors in recent years have gone after shady dealers, such as Frederick Schultz, a prominent New York art dealer now serving a 33-month sentence for trading in stolen Egyptian antiquities.
In a memorable Philadelphia case, the FBI set up a successful 1997 sting to recover a 1,500-year-old Peruvian "backflap" - a piece of gold armor worn by warriors - looted a decade earlier from a Mochu lord's grave in northern Peru.
While Peru got the US$1.6 million (euro1.22 million) treasure back, the Miami smugglers - who tried to sell it to an undercover agent - spent just a few months in prison. The real target of the probe - Panamanian ambassador Francisco Iglesias, who allegedly helped get the large piece to New York through diplomatic mail - fled the United States and remains a fugitive.
Assistant U.S. Attorney Bob Goldman, one of two federal prosecutors on the FBI task force, handled the backflap case and others involving a Civil War expert who staged phony appraisals on the PBS series "Antiques Roadshow" and antique gun dealers who conned a Colt firearms collector out of about US$20 million (euro15.28 million).
"Every which way you can defraud somebody, it's taking place in the high-end art industry," Goldman said.
Federal prosecutors in Philadelphia say they've prosecuted about US$100 million in art fraud in the past four years alone.
At Penn's museum Thursday, archaeologist Clark Erickson described the pervasive looting that experts say has ravaged nearly all of Peru's ancient archaeological sites. The looters - locals who can make as much as US$1,000 (euro764) selling a sought-after find to middlemen - are increasingly market-savvy, switching their hunt from metals to textiles, for instance, as demand and prices change.
Archaeological sites in poor or unstable countries - including Iraq and Afghanistan - are the most vulnerable. Experts have reported massive looting in Iraq since the fall of Saddam Hussein, whose regime threatened looters of antiquities with the death penalty.
"With some of new anti-terrorism laws, I expected this huge increase in announcements about intercepting smuggled archaeological material," Erickson said. "And it doesn't seem to be happening."