Harvard molecular biologist Don Wiley was last seen leaving a banquet in Memphis just before midnight on Nov. 15. His rental car was found a few hours later, abandoned on a Mississippi River bridge with the keys in the ignition and the tank full of gas.

His family does not believe he committed suicide and police say there is no evidence that the 57-year-old married father of four with no known financial or domestic problems was kidnapped or killed.

But the disappearance in this time of war and anthrax attacks has attracted the attention of the FBI. Wiley is an expert on how the human immune system fights off infections and had recently investigated such dangerous viruses as AIDS, Ebola, herpes and influenza.

Investigators are reviewing all possibilities to what might have happened, from Wiley's jumping from the bridge to his being a target of some kind of terrorist-backed kidnapping because of his research.

"Right now nothing is pointing at anything, except he is missing," police Lt. Walter Norris said Tuesday.

Wiley's wife, Katrin Valgeirsdottir, said "suicide is everybody's first reaction" but she doesn't believe her husband would have killed himself.

She said "there is no connection to terrorist activity. None."

"We don't know what happened. We can speculate until the cows come home but we don't know," she said in a telephone interview from Cambridge, Mass.

Wiley is a professor of biochemistry and biophysics in Harvard University's molecular and cellular biology department. He and another Harvard professor, Dr. Jack Strominger, have won honors for their work on how the human immune system works, including the Japan Prize two years ago.

Wiley was in Memphis to attend a two-day annual meeting of the scientific advisory board of St. Jude Children's Research Hospital, a board Wiley has served on for about 10 years.

Professors at Harvard and board members at St. Jude's announced Tuesday that they're offering a $10,000 reward for any information that helps find Wiley.

Dr. William Evans, St. Jude's deputy director, said Wiley seemed "in a great frame of mind" and was looking forward to time with his family when he left a Nov. 15 dinner at the Peabody Hotel about midnight.

Four hours later, police found Wiley's abandoned Mitsubishi Galant a few miles from the hotel, in a lane of the Hernando DeSoto Bridge that rises 100 feet above the Mississippi River between Memphis and Arkansas.

Norris said police have no clues as to Wiley's whereabouts during those four hours. He said patrol boats and helicopters have been checking the river, but divers wouldn't be helpful because the current is too swift.

Valgeirsdottir reported her husband missing Nov. 16, the day she and their two children had planned to meet him in Memphis. She said Wiley had been staying with his father in a Memphis suburb.

She said she could think of no reason he would have driven toward Arkansas after the hotel dinner.

Wiley's 85-year-old father, retired chemist Bill Wiley, said his son knew his way around the city from years of visits and attending the hospital meetings.

"We can't accept the suicide theory," Bill Wiley said.

Police Inspector Jerry King said there was nothing to support theories that Wiley was a victim of a crime or he disappeared because of a domestic or financial situation. Investigators have been dusting the rental car for fingerprints and performing other tests, but nothing has turned up so far.

William Woerner of the FBI's office in Memphis said the agency was not conducting an investigation into Wiley's disappearance.

He said the agency was interested in the case because Wiley is a prominent scientist but there was no evidence the disappearance is related to his profession.

FBI spokesman George Bolds said the FBI would assist Memphis police if needed, but the disappearance is a missing persons case for now.

"There are many possibilities and theories as to what could have happened," Bolds said. "There is not a whole lot the FBI can add right now."