Annie M. Le, 24, planned to get married Sunday.
Le is a doctoral student in pharmacology at Yale. She was last seen at a research laboratory at 10 Amistad St. and has not contacted her family, co-workers or friends.
Debbie Apuzzo, who works in the pharmacology department, said Le was excited about getting married. She describes Le as energetic and conscientious.
Le is of Asian descent and has brown hair and brown eyes, 4 feet 11 inches tall and she weighs 90 pounds.
Her purse -- containing her cell phone, credit cards and money -- was left in her office, police said.
Le's professors, colleagues, friends, family and fiance are assisting in the investigation, Yale Chief of Police James Perrotti said in a news release.
Security officials are reviewing images from closed-circuit cameras in the area near where she was last seen, police said.
Le got her undergraduate degree from the University of Rochester in New York. She majored in cell and developmental biology with a minor in medical anthropology.
She also conducted a summer project at the National Institutes of Health on bone tissue engineering using mouse mesenchymal stem cells, according to a biography posted on the NIH Web site.
At the University of Rochester, she did research involving parasitic wasps.
She previously worked as a lab assistant in the Pathology Department of Marshall Hospital in Placerville, according to the biography.
KCRA contributed to this report.