Vermont police have released a sketch of a person of interest in the case of a retired college dean who was found shot in the head last week.

Honoree Fleming, 77, was discovered dead on 5 October on a hiking trail near Vermont State University Castleton Campus, where she used to work.

The sketch was based on witness descriptions of a man they saw enter the trail before her body was found.

The killing has shocked the small town of Castleton, Vermont.

Police say the suspect is a 5ft 10in (1.78m) white male with red hair who seemed to be in his 20s. They say he wore a dark grey T-shirt and a black backpack and is armed and dangerous.

“There was more than one witness that observed this individual just prior to coming across Miss Fleming’s body,” Vermont State Police Captain Scott Dunlap told a news conference on Wednesday.

He said without elaborating that the potential suspect was observed to be “acting very strangely”.

It is unclear if the shooting was targeted or random.

Officials did not release any other details about the case, which has been ruled a homicide.

The Burlington Medical Examiner’s office determined Ms Fleming died from the gunshot wound to the head.

She was attacked while on her regular afternoon walk last Thursday along the Delaware and Hudson Rail Trail, a 20-mile (32km) section of former railway that is used by pedestrians and cyclists.

Ms Fleming was the dean of education at Vermont State University before she retired in 2012. In a statement on Facebook, the college said more police would patrol the campus.

The university said Ms Fleming was beloved by faculty, staff and students. A professor of education and biochemist, she was still publishing academic papers on cellular biology.

“Her contributions to education and her impact on our campus will live on in all of us,” the college said.

Ms Fleming lived in Castleton with her husband Ron Powers, who in 1973 became the first television critic to win a Pulitzer Prize.