A car belonging to a missing couple was found a few miles from the gated yacht community where they live part time, but yielded no clues about their whereabouts, authorities said.

John and Elizabeth Calvert were last seen Monday. Co-workers began to worry about the typically punctual couple when they missed business meetings the next day.

Police found the Calverts' silver 2006 Mercedes on Friday at a resort a few miles from the Harbour Town Yacht Basin, but there was nothing in the car to explain the couple's disappearance, Beaufort County Sheriff's Lt. Col. Neil Baxley said.

Lightning caused authorities to call off a search of the marina using divers on Friday. Baxley would not say why they wanted to look in the water and released few details about the search, except to say that the FBI and state police were also involved.

"We're exploring everything and anything," he said. "Everybody's got their eyes open and their ears open."

Authorities say the Calverts' cell phones have been turned off since Tuesday. The small airplane owned by Elizabeth Calvert, a pilot, was found undisturbed on the tarmac at the island's airport. The couple's cat was still on their yacht.

The Calverts have a home in Atlanta and lease and manage the Harbour Town marina, where they live on their 40-foot yacht, the Yellow Jacket. Their company also manages rental units and other businesses on Hilton Head Island, an upscale golf resort island near the South Carolina-Georgia line.

The car was found at a parking lot at the Palmetto Dunes resort. The Calverts don't own or manage property at the resort, said co-worker and friend Tony Gibus.

He and others have been posting fliers with photos of the couple across the 12-mile long barrier island and in Savannah, Ga., about 45 miles away.

Gibus said Friday he knew something was wrong when John Calvert, 47, missed a meeting Tuesday morning to plan promotions and budgeting for the marina's upcoming spring season.

"When I came out at 11:30 that morning, their boat looked undisturbed and we wondered if they'd just slept in," Gibus said. "But he's never missed a meeting and he's never turned off his cell phone. They would never just run off."

Elizabeth Calvert, 45, works as an attorney in nearby Savannah. She failed to report for meetings Tuesday at HunterMaclean, where she specializes in employee benefits and executive compensation, said John Tatum, the firm's managing partner. She previously had been a corporate attorney for UPS in Atlanta.