A business executive questioned by investigators in a couple's disappearance apparently committed suicide by slashing his inner thigh with a knife, the Beaufort County sheriff said Thursday.

Sheriff P.J. Tanner told reporters Dennis Ray Gerwing had been dead for several hours before investigators identified him as a person of interest in the case Tuesday. Gerwing's lawyer found his body in a condominium on this tiny resort island about 90 minutes after the sheriff's office made his name public.

"It appears, based on preliminary autopsy results, that he had been deceased for about 12 hours before our arrival," Tanner told reporters at a news conference. When asked whether foul play had been ruled out in Gerwing's death, Tanner said the death remained under investigation.

Gerwing's death added another layer of mystery to the disappearance of John and Elizabeth Calvert, who were last seen March 3. John Calvert, 47, and his 45-year-old wife run several businesses in the area, including managing boat slips at the marina where they live part time on a yacht in the gated Harbour Town community, known for its candy-cane-colored lighthouse.

Gerwing, 54, was chief financial officer of The Club Group, which the Calverts hired more than two years ago to run administration, accounting and human resources for their business. In December, Calverts decided they no longer needed the company and Gerwing was leading the transition out.

Tanner declined to say if investigators believe Gerwing had a direct role in the Calverts' disappearance or if others were involved, saying only that the investigation is ongoing.

The sheriff said Gerwing's death "creates on one hand challenges, and on the other hand answers," though he wouldn't say what those answers might be.

"Dennis Gerwing was the last person we know that saw the Calverts on that Monday afternoon," Tanner said. "We questioned him one time and attempted to set up another interview with him."

Tanner said Gerwing had got an attorney and was not cooperating.

Investigators found two suicide notes with Gerwing's body, but Tanner refused to discuss their contents or say if they contained any clues to what happened to the Calverts. He said the notes were still being analyzed by police.

The sheriff also would not answer directly when asked if he believes the Calverts are alive or dead.

"We're looking at the worst case scenario and hoping for the best," he said.

The case has been the talk of this slipper-shaped, 12-mile golf resort island near the Georgia border. The couple's 40-foot yacht, The Yellow Jacket, has become an attraction, with passers-by stopping to take pictures.

Authorities say the Calverts' cell phones had been turned off when they were reported missing last week. A small airplane owned by Elizabeth Calvert, a pilot and a business attorney in nearby Savannah, Ga., was found undisturbed on the tarmac at a local airport.

The couple's silver 2006 Mercedes was found last Friday, but authorities said it offered no clues to the Calvert's whereabouts. The Calverts also owned a home in Atlanta, but it also hasn't yielded any clues.