University officials said Sharpe's affiliation with HMS began in 1985, when he was a research fellow in the Wellman Laboratory.

After a year in the laboratory of Dr. Richard Granstein, now a professor at Cornell University, he became a resident in the HMS Academic Department of Dermatology, a position that he held from July 1987 to June 1990.

Following his residency, he was a full-time instructor in dermatology at HMS from mid-1990 to 1993, a position that involves seeing patients, teaching and making rounds with students in a patient setting.

Colleagues React

Sharpe's former HMS colleagues said his behavior was not suspicious.

Dr. Kvedar, who supervised Sharpe at points during his residency, said that he was a motivated, goal-oriented student.

"A lot of it is shocking," Kvedar said. "He was very, very bright, very directed and had very clear ideas of where he wanted to take his life and where he wanted to go."

Dr. Steve Shama, a clinical instructor in dermatology at HMS, said that Sharpe was also a leading donor to the Dermatology Foundation, an organization that underwrites research in the field.