By David Abel, Globe Staff, and Michele Kurtz, Globe Correspondent, 12/20/01

Five weeks after Harvard University biochemist Don Wiley mysteriously disappeared in Memphis, police today found his body floating 320 miles to the south in a river tributary in Louisiana.

Don C. Wiley (AP Photo)

Wiley's body was discovered shortly before 10 a.m. snagged to a tree in log-strewn water next to the Hydro Electric's S.A. Murray Jr. Station in Vidalia, Louisiana.

Police found a wallet with documents that identified the body as Wiley, a 57-year-old nationally acclaimed expert in infectious diseases. FBI officials in New Orleans notified Memphis police at 3:15 p.m. today, and local officials tonight sent the remains to the Shelby County Medical Examiner's office in Memphis.

Officers in Memphis said they need to await the findings of an autopsy before the city medical examiner officially identifies the body or the cause of death.

``That is all we know right now,'' said Officer Latanya Able, public information officer for the Memphis Police Department. ``This is very sad and our hearts go out to the family.''

Wiley was last seen around midnight on Nov. 14 at the historic Peabody Hotel, while attending a two-day annual meeting of the scientific advisory board of St. Jude Children's Research Hospital.

At 4 a.m., police found Wiley's rental car on a mile-long bridge that spans the Mississippi River, with his rental-car contract in the glove compartment, the keys in the ignition, and a full tank of gas. The Mitsubishi Galant was pointed west, the opposite direction from Wiley's father's home, where the professor was planning to spend the night.

Since then, police combed the river and the city but could find no clues to what happened to the professor, whose work was of the caliber that could have made him a candidate one day for the Nobel prize. He had already received the prestigious Lasker and Japan awards.

Speculation about his death ranged from suicide to a violent mugging to some sinister plot by bioterrorists. But every theory has had serious flaws.

Wiley had planned to spend the weekend with his wife and two young adopted children in Memphis, and the family had bought tickets to visit Graceland.

In addition to two adult children, Wiley also had a brother, and an 82-year-old father, who live in Memphis.

His family and friends have consistently insisted he would not commit suicide.

Wiley had no history of mental health problems, no family or financial problems, and he was actively involved in raising his two adoptive children, ages 7 and 10. His wife, Katrin Valgeirsdottir, said she and her husband had bought tickets to fly to Iceland and that Wiley had been spending time learning Icelandic, her native language.

Neither Valgeirsdottir nor other family members could be reached last night for comment.

In a statement, Harvard President Lawrence Summers said tonight, ``All of us are profoundly saddened by today's news. Don Wiley was a brilliant biologist and a greatly admired member of this community. His loss leaves a tremendous void.''

Wiley, an expert on how the immune system fights infection, had recently studied the Ebola virus, HIV, herpes, and influenza.

The professor was most widely known for his work in X-ray crystallography. He was widely regarded as the nation's foremost expert in using special X-ray cameras and mathematical formulas to make high-resolution images of viruses.