A retired Vermont university dean was killed while she was walking on her favorite trail Thursday afternoon near the campus where she once taught.

Honoree Fleming, 77, a respected biochemist and cell biologist , was shot in the head around 4 p.m. on the Delaware and Hudson Rail-Trail near the Vermont State University Castleton campus, where she served as Dean of Education before her retirement. Her body was found about half an hour later, and witnesses described seeing a red-haired white man, approximately 5 feet, 10 inches tall, whom the Vermont State Police has named as a person of interest. He has not been apprehended, and police warned that he was considered armed and dangerous, and urged residents to be vigilant.

We dont have a suspect, we dont have a motive, Maj. Dan Trudeau, commander of the Vermont State Polices Criminal Division, said in a news conference Monday afternoon, but noted that the agency had received more than 200 tips from the public. Investigators are specifically asking people who were walking or biking on the trail between 3 p.m. and 5 p.m. on Oct. 5 to come forward. They are continuing to search the area with the help of the Castleton and Fair Haven police departments, New England K9 Search and Rescue, and other agencies.