"She excelled," Siegel said from Palo Alto, Calif. He taught Ketunuti a course in microbiology and infectious disease.
"And she had a great personality - smiling, easy to get along with."
Siegel said Ketunuti, who graduated from Stanford in 2007, was married at the time to another of his students, Geoffrey Smith. The two met when they were undergraduates at Amherst (Mass.) College, Siegel said. An Amherst official confirmed that Ketunuti graduated from the college in 1999.
Siegel said the couple divorced and remained friends. Smith, a physician who also holds a Ph.D in microbiology, could not be reached for comment.
At Stanford, Siegel was so taken with Ketunuti's abilities that he made her his teaching assistant.
"Anybody who TA'd for me has a residual place in my pantheon of greatness," Siegel said.
As an assistant, Ketunuti had to teach sections of the microbiology course after completing it. That was impressive, Siegel said, because she was just a year older than the students she was teaching.
"She gained respect of students who were contemporaries," he said.
Siegel, who is listed as a Facebook friend of Ketunuti's, said the two had not spoken in years.
He added that Ketunuti, an avid runner, was the daughter of a Thai father and a Belgian mother.
Ketunuti, on her Internet blog, appeared as a citizen of the world, referencing "adventures and wild escapades" including eating meat with her hands in Botswana, where she conducted AIDS research.
Her listing of hundreds of Facebook friends looks like a roster of some of the best and brightest on several continents. A large proportion of Ketunuti's friends graduated from sterling schools, and many perform important medical jobs, often in the service of sick children.
Ketunuti's friends and family declined requests to talk about her life. After raising the possibility during the day Thursday that Children's would allow Ketunuti's colleagues to speak about her work, officials in the evening declined to make anyone available.
That no one would speak for Ketunuti seems in keeping with a quote from the actor and playwright Harvey Fierstein posted on her blog: "Accept no one's definition of your life; define yourself."
Contact Alfred Lubrano at 215-854-4969 or email@example.com.