Sellers beware -- of online posses

The pieces of Hollywood history were priced to move, even by the discount standards of EBay. Ten bucks put a bidder in the running for a dagger purportedly used in the filming of "Gone With the Wind," a decanter from "I Love Lucy" and a birdhouse from "Lord of the Rings." Bidding for other memorabilia, including a vase said to be from "Casablanca," opened at only 99 cents.

The bargain-basement prices offered by a Marina del Rey antiques dealer this spring sparked two reactions online: furious bidding and deep suspicion. As fans drove the prices up -- the dagger sold for $713 -- a group of seasoned collectors from across the country became convinced the items were phony.

"The most obvious fakes I'd ever seen," pronounced James Tumblin, a Hawaiian who said he owns the world's largest collection of "Gone With the Wind" memorabilia.

Frustrated by the lack of response from police, the collectors became a sort of Internet posse. They traced the dagger to a factory in modern-day Japan, the birdhouse to a Big Lots and the vase to the former West Germany -- a country whose existence postdated "Casablanca" by seven years.

They used their findings to warn away other bidders and lobby EBay to shut down online stores selling the dealer's merchandise.

"I really felt people had a right to know," said Jennifer Henderson, a vintage clothing collector who said she and her husband, Bryce, spent more hours "than I am comfortable admitting" investigating the dealer, Global Antiques.

EBay suspended the two Culver City consignment stores that listed the items last month. One of the consignment stores, AuctionDepotLA, has since closed.

Neither Global Antiques owner Greg Jones nor representatives of the consignment shops returned calls. No charges have been brought against Jones, Global Antiques or any of the stores involved. In a statement, EBay said privacy policies prevented it from disclosing the reasons it shuttered the auctions of those selling Global Antiques' merchandise.

Auction fraud is the most commonly reported crime online, according to the federal Internet Crime Complaint Center, also known as the IC3.

As local police and auction houses struggle to keep up, citizens are increasingly stepping in to the gap and making what amount to cyber citizen arrests.

"Our speculation is that the posse mentality can take care of these situations faster than the host can," said Craig Butterworth, a spokesman for the National White Collar Crime Center, which jointly administers the IC3 with the FBI.