ELLSWORTH, Maine — Thieves who steal for profit are getting more and more sophisticated.

Not only are they figuring out ways to outsmart the latest surveillance systems and equipment in retail stores, many are using the Internet to “e-fence” their ill-gotten gains on shopping sites such as eBay and Craigslist.

Walt Huffman, loss prevention manager for Marden’s Surplus and Salvage, which has 14 stores in Maine, estimates that as much as 40 percent of the new merchandize sold on Internet shopping sites is stolen.

The thieves also are becoming highly organized, managing to clear out entire shelves of costly electronics and other goods before store personnel even realize what’s hit them.

The thieves often trade stealing tips and information about various stores’ security weak spots while spending time in jail, Huffman said in a recent interview.

“The bad guys are talking to each other — why shouldn’t we?” he said.

That’s why Huffman and others in the retail business are working to bring together merchants, law enforcement officials, prosecutors and others with a stake in preventing theft and fraud.

Huffman is working to set up groups in the 14 communities in which Marden’s operates so that retailers and others can share ideas, “talk shop” and look at trends.

One such meeting took place this week in Ellsworth, where a police detective and representatives of a discount store, a shoe store, an outfitter and a grocery store, to name a few, traded information of their own, including strategies for outsmarting would-be shoplifters.

They also passed around a stack of mug shots of local people recently arrested for theft.

Curtis Picard, executive director of the Maine Merchants Association, is among those heading the effort to curb organized retail crime.

“I can tell you that nationwide, it’s a $30 billion problem,” Picard said Thursday in a telephone interview. He said, however, that an estimate of retail theft losses in Maine is not available.

“I think [if a dollar figure was available] it would probably surprise a lot of folks,” he said.

Huffman suspects the losses are “probably in the millions” each year.

In addition to outright shoplifting, he said, thieves are switching price tags and UPC codes, returning stolen merchandise for cash or store credit and writing bad checks to buy gift cards, which they then sell at a reduced price.

Organized retail theft is an emerging problem in southern Maine, which is handy to markets in Boston, Huffman said. As the economy worsens, the problem eventually will work its way north, Huffman and Picard believe.

The main markets for stolen goods, Huffman says, are:

ä The street, where the stolen goods fetch about 20 percent of their retail prices.

ä Yard sales and flea markets, where thieves are making about 50 cents on the dollar.

ä Internet sites, such as eBay and Craigslist, where the items can be sold in virtual anonymity and on a large scale.

Huffman said that former Attorney General Steven Rowe established a task force to address organized retail theft in Maine. Maine officials also have joined forces with their counterparts in other New England states.

Huffman and other retailers say that stiffening penalties for shoplifting would make Maine less attractive to thieves.

In Maine, shoplifting is not a felony unless the amount stolen totals $1,000 or more, compared to $250 in Massachusetts and $500 in New Hampshire.

Another step merchants say would help deter criminals would be to group charges against an individual stemming from multiple counties, Huffman said.