But while Wiley’s brother and sister-in-law said that they appreciated the MPD’s thoroughly investigating all leads, the tips Shemwell told them about seem unlikely to make a major contribution to the search.

“They had someone who said they saw him at a garage sale,” Susan Wiley said.

True himself cautioned that tips inspired by rewards have a low success rate.

“Most of these leads will turn out to be nothing,” he said. “But if one lead out of 500 turns out to be conclusive, it’s worth it.”

Employees at the Peabody say they have told the MPD and the hotel all they remember of Wiley’s behavior that evening.

One Peabody staff member said Wiley had been given a handmade American flag pin made out of beads and safety pins that night, and that he planned to wear it the next day at the conference’s closing session.

The employee said Wiley, who stayed for cocktails at the Peabody’s lobby after the banquet ended, was the last of the conference attendees to leave the bar.

At Harvard, administrators are waiting for an announcement from Memphis before they address Wiley’s academic commitments.

Wiley is scheduled to co-teach Biological Sciences 56: “Structure, Function, and Physical Chemistry of Macromolecules” with Higgins Professor of Biochemistry and Molecular Biology Stephen C. Harrison in the spring.

Andrew P. McMahon, Baird professor of science and chair of the Department of Molecular and Cellular Biology, said the department has made no changes to its spring course offerings as a result of Wiley’s disappearance.

If necessary, changes will be made “in enough time to be able to teach the course,” McMahon said.

—Jenifer L. Steinhardt contributed to this article.

—Daniel K. Rosenheck can be reached at rosenhec@fas.harvard.edu.

—Elisabeth S. Theodore can be reached at theodore@fas.harvard.edu.