PANAMA CITY, Panama -- When William and Jane Cortez came to Bocas del Toro, they seemed like any other couple looking for the laid-back island living that has attracted so many expatriates to Panama's Western Caribbean archipelago.

What neighbors could not have suspected was that ``Wild Bill,'' as he called himself, and his partner were really 30-year-old William Dathan Holbert and Laura Michelle Reese -- fugitives wanted for property fraud in the United States and featured in 2006 on America's Most Wanted, the television crime show.

Now Panamanian authorities suspect the two may be serial killers who murdered two of their Bocas del Toro neighbors -- and possibly others -- in order to take over their property. Panamanian police have confirmed they found two bodies in shallow graves behind the Cortez home. In a Thursday night news conference, they said there could be as many as 10 victims in a killing spree that may have spanned three years.

An international manhunt began June 20 when Panamanian police discovered the graves of Cheryl Hughes, a former Florida resident, and a man believed to be Bo Icelar.

On Monday, Nicaraguan forces caught the couple as they fled across the San Juan River from Costa Rica. They were extradited to Panama Thursday. As he got off the plane in Panama City, Holbert shouted: ``Long live Panama. Thank you for the free trip.''

The America's Most Wanted website says Holbert once lived in North Carolina and ran a white supremacist store but was almost constantly on the move. Reese, 27, also lived in North Carolina at one time.

Members of the shaken Bocas del Toro community say they had no idea who the people they knew as William and Jane Cortez really were. But they appeared to do quite well for themselves as they registered lots, houses, islands and corporations under the name of Jane Seana Cortez in what now appear to be illegal transfers.

The Cortezes came to Bocas del Toro in 2007 and moved into a home they allegedly purchased from Mike Brown who lived with his wife and teenage son in a remote area called Cauchero, an hour by boat from the main islands. The Browns have not been seen since the Cortezes arrived, but those who knew them said they thought the family had moved to Thailand.

Neighbors described the man they knew as ``Wild Bill'' Cortez as rambunctious and big -- carrying 280 pounds on his large frame.

They said he drank heavily and was prone to stunts during wild parties he threw at a social club he built where Bocas residents would meet up to drink beer, barbecue and go swimming.

In August last year, the Bocas Breeze newspaper carried an advertisement for the opening party at Wild Bill's Jolly Roger Social Club, just down the shoreline from the couple's Cauchero home. Decorated with skulls and crossbones, it promoted the bar as the only expat membership club in Bocas with the slogan: ``Only 90 percent of our members survive.'' Its location was listed as Cauchero at Cutthroat Cove.

Jane Cortez, described as heavy-set and red-haired, placed for-sale classifieds in the local paper, including discounted aircraft and boat moorings, as well as ``hassle-free and quick closings'' for houses, businesses and boats.

It was not until Bocas resident Cher Hughes disappeared in March that suspicion began to grow that the Cortezes might not simply be a wealthy entrepreneurial couple. Hughes, in her early 50s, was known in the community for her bright smile and winning personality.