AMHERST, Massachusetts (Reuters) ― An epidemic of sculpture knock-offs is plaguing the art world, and just like the sale and production of counterfeit designer handbags and shoes, law enforcement is having a difficult time keeping up.

Statues, wildlife figures and, in one case, a copy of Jasper Johns’ 1960 metallic collage “Flag,” are turning up for sale in stores, garden centers and other outlets without the approval of the artists who originally created them, and sometimes at top-end prices.

American sculptors say they are losing income and spending tens of thousands of dollars in legal expenses trying to track down and stop the knock-offs, often with little success. Many of the forgeries come from foundries in Asia, while advances indigital scanning and photography are making copycat sculptures even easier to create.

Art crime police say it is difficult to estimate the scale of the trade in fakes. “There is a significant problem of knock-offs in all areas of the art world,” Robert K. Wittman, retired founder of the FBI’s Art Crime Team, told Reuters.

He cited an Interpol statistic of $6 billion in annual art crimes around the world, of which the majority are forgeries. Unauthorized sculpture castings are classified by the FBI and Interpol as forgeries.

Eli Hopkins, business manager for his father, Colorado-based wildlife sculptor Mark Hopkins, said he found fiber glass copies of his father’s bronzes in a Hobby Lobby arts and crafts store selling for one-tenth the price of the originals.

“I used to get catalogs of decorations just to look for copycats, but I just stopped after a while,” Hopkins told Reuters. “I got too stressed out finding things and then finding out that I couldn’t do anything to stop it.” Over the years, he and his father, whose work has been collected by McDonnell Douglas Corp and former President Bill Clinton, among others, have spent more than $75,000 in legal expenses, hiring lawyers to write cease-and-desist letters, occasionally going to court and only sometimes meeting with success.

“You try to get the judge to award legal fees but that doesn’t always happen,” he said. The real culprits, Hopkins said, are foundries in China and Thailand that produce knock-offs and who appear to be outside the reach of the law.

The same problem happened to Jane Dedecker, a sculptor in Loveland, Colorado, whose works have been collected by television hostess Kathie Lee Gifford and actor Arnold Schwarzenegger, among others. She first discovered unauthorized reproductions of her work 10 years ago at a garden store.

One of the sculptures looked like hers and bore her signature but it wasn’t made by Dedecker and the price ($6,000) was less than one-third of the $21,000 she charged for the original version. Dedecker and her business managers say they have identified approximately 30 of her sculptures that have been reproduced by unknown others.

On occasion, a culprit is found. In November, Brian Ramnarine, owner of the Empire Bronze Art Foundry in Long Island, New York, was charged with one count of wire fraud after he attempted to sell both privately and through an international auctioneer an unauthorized copy of Johns’ 1960 metallic collage “Flag” for $11 million.

The foundry was known to Johns, who, in 1990, had brought a mold for the sculpture to the foundry in order to create a wax cast of the piece, according to the U.S. Attorney’s office in Manhattan.