It is two weeks since the body of Northern Virginia real estate developer C. Daniel Swansen was found wrapped in a bedspread and bound with wire in the back of his camper alongside Interstate 95 in South Carolina.

Swansen, 52, had been killed by a bullet in the back of the head and police there say they discovered his body after a state trooper was gunned down when he apparently tried to search the van.

Three suspects have been arrested and charged in the trooper's death, but as yet no charges have been filed in Swansen's. Little is known about the exact circumstances of Swansen's slaying, but what emerges from the police investigation and from independent interviews is a portrait of a successful man who seemed shattered by the accidental death of a son several years ago and whose behavior since had grown increasingly erratic.

According to investigators, Swansen, married and the father of three, spent the last hours of his life driving the 33-foot Holiday Rambler camper south in the company of three hitchhikers -- two male, one female. One was an ex-convict and the girl was a teen-aged runaway.

Before he was killed, authorities said, the four occupants of the camper appear to have engaged in a drunken orgy. Wine bottles, both empty and unopened, littered the interior.

Also found in the vehicle were a number of X-rated videocassettes and pages torn from pornographic publications, police said.

The bizarre odyssey seems a total departure from the public perception of Swansen, who had built houses all over Northern Virginia -- including the Briarwood subdivision in Annandale in which he lived -- and who was viewed as a private man who preferred the company of his family or one or two friends.

But those closest to him say that he remained deeply depressed since his son's death, and that he had begun to drink heavily.

Richard Fialkowski, chief of police in Hardeeville, S.C., said he had learned that Swansen's recent behavior had been what he described as "eccentric," marked by spending sprees and by a desire to befriend strangers.

In August, Swansen and his wife, Deanna, left their home in Annandale for the North Carolina coast where they kept a 36-foot sailboat, Prelude II, in the town of Oriental, near Pamlico Sound.

On Aug. 15, the Coast Guard in Morehead City, N.C., received a call from a tugboat, Fialkowski said. A woman had been spotted on the deck of the Prelude II, waving her arms.

It was a call for help, and Swansen was taken from the boat to the Brynn Marr Hospital, a psychiatric facility in Jacksonville, N.C., where he was diagnosed as being manic, Fialkowski said.

Fialkowski said Swansen was released from the hospital in mid-September and that Swansen and his wife apparently spent the night of Sept. 25 at a camper park in Emerald Isle, N.C., just south of Morehead City.

His wife left early the next morning to return here for a doctor's appointment, according to Swansen's mother, Frances. His wife could not been reached for comment.

The manager of the camper park could not remember the Swansens, but the foursome later made up by Swansen and his three new traveling companions proved more memorable.

Authorities said they believe that Swansen picked up the first hitchhiker, a North Carolina man identified as Richard C. Johnson, 22, in the Morehead City area a short time after his wife left the camper park.

Fialkowski said Swansen was carrying three guns in the camper -- a .357 magnum, a .38 caliber revolver and a 12-gauge shotgun.

Johnson, a former carpet installer and carpenter, served a five-year sentence in North Carolina for a break-in at a furniture store and driving under the influence of alcohol, a state corrections spokesman said.

Swansen and Johnson headed south, Fialkowski said, and at 11 p.m. Sept. 26 they picked up two more hitchhikers at a rest area on I-95 just south of Florence, S.C., about 150 miles from Morehead City.

One was Connie Hess, 17, who was reported missing in Omaha on Sept 1. In an interview last week, her father described her as a chronic runaway and said she had been treated for six months at an Omaha psychiatric clinic.

Authorities said Hess apparently had met the third hitchhiker, Curtis Harbert, in Nashville.

Previously, they said, he had worked at two fast-food restaurants in Moorefield, W.Va., and had served three days in jail there after being convicted of passing bad checks. He was nicknamed "Stretch" by his friends because of his 6-foot-4, 160-pound build.

About 11:30 p.m., all four ate at the Beef and Bacon Restaurant in Florence. Helen Blue, a waitress there for five years, said she clearly remembered Swansen and his companions. Swansen wore a clean sports jacket, Blue said. The other three wore dirty, faded jeans, and "one of the dudes had a headband."

She remembered their orders. Swansen had two eggs over light, grits, sausage, ham, bacon, coffee, milk and orange juice. The other three had burger platters. They made no trouble, and because of their attire, Blue said, she took them to be workers in a carnival that had come to town.

She recalled that Swansen "was talking and smiling and he laughed. He said what a nice restaurant we had."

He left a tip of $10. In dimes, Blue said.

Three hours later, about 2:30 a.m. Sept. 27, the camper pulled in to Dorrell's Exxon station in Turbeville, S.C., about 30 miles south of Florence.

In the interim, authorities said, the group may have pulled to the side of I-95 and had a party. At some point during the evening, investigators believe, the woman in the van had sex with all three men, according to South Carolina prosecutor Randolph Murdaugh Jr.

At the Exxon station, attendant Glenn MacKenzie said the vehicle's occupants were "talking a bunch of nonsense." He said Swansen was happy but incoherent.

MacKenzie said Swansen boasted about his intelligence and that he bought 4,000 small firecrackers, on sale for $12.50 and legal in South Carolina.

"He told me he was going to Florida to shoot the fireworks," MacKenzie said.

Later that morning a South Carolina state trooper apparently spotted the camper parked by the side of I-95 near the town of Santee, and ordered the occupants to move it, Fialkowski said.

Then, about 9 a.m., a second state trooper, Bruce Smalls, received a report that a trucker had spotted a camper with Virginia plates weaving down I-95 near Hardeeville.

"The trucker said: 'You better check it out; they're going to kill somebody,' " recalled state police Capt. B.H. Jones. There had been another report about the same time indicating that a woman inside the van was exposing herself to the occupants of passing cars.

Smalls flagged down the camper on I-95 about four miles north of the Georgia border and directly across from a South Carolina Welcome Station, and parked a few yards behind it, according to authorities.

He spoke briefly with the three occupants of the camper, then asked to search the vehicle, apparently for liquor and drugs, Fialkowski said.

As the trooper stepped up to the passenger door, he was shot at least twice in the chest at point-blank range with a .38 caliber pistol, Fialkowski said.

He fell onto his back, authorities said, and was shot at least twice more in the face.

The camper was left with the motor running, and Johnson was arrested on foot along I-95 about two miles north of the shooting site, authorities said.

About 45 minutes after the shooting, they said, Hess and Harbert emerged from a clump of brush in the highway median strip near the camper and were taken into police custody.

Swansen's body was found in the back of the camper, stuffed behind a bed. Also in the van, authorities said, was $1,000 in cash belonging to Swansen as well as about $40,000 in certificates of deposit in his name.

Fialkowski said Hess had a gold chain and that Johnson had a .357 magnum pistol believed used in Swansen's killing and two gold rings and a gold Rolex watch that belonged to Swansen.

Authorities said many aspects of the case remain unclear. They believe Swansen was shot as he slept, but they have so far been unable to determine exactly when or where, and that fact is making prosecution of the case difficult.

South Carolina authorities said that murder trials for the three in the death of Smalls, a father of two young children and president of an elementary school PTA, could begin as soon as mid-November.

All are being held without bond and have not entered pleas, authorities said.

Prosecutors, believing that Johnson killed the officer, have indicated they will seek the death penalty, according to Johnson's defense lawyer, Darrell Thomas Johnson Jr.