CASTLETON, Vt. (AP) — Vermont police on Wednesday released a sketch of a person of interest in the killing of a retired college dean who was shot dead last week while walking on her favorite trail near the Vermont State University campus.

The crime has shaken the small college town as police warn the public to remain vigilant.

The composite sketch was created from witnesses’ accounts of a man they saw on the trail before they came across Honoree Fleming’s body, said Capt. Scott Dunlap, commander of the Vermont State Police major crime unit. Fleming died of a gunshot wound to the head while walking along the trail that follows a former railroad bed, police said.

The man was described as 5-foot-10 (1.78-meter) white male with short, red hair, who appeared to be in his 20s. He was wearing a dark gray T-shirt and carrying a black backpack, and is considered armed and dangerous, police said.

Witnesses reported that the man was acting odd, Dunlap said, but he would not elaborate. More than one person observed the man but Dunlap would not say how many.

“Person of interest, suspect, it’s definitely somebody we want to talk to,” he said.

Students and residents in the small Vermont town of Castleton were being told to lock their doors and stick together as police have been searching for the killer.

Fleming was a retired dean and professor of education at what was called Castleton State College and is now the Vermont State University Castleton Campus. She was found shot to death Thursday afternoon about a mile (1.61 kilometers) south of campus.

Police spokesman Dunlap said Wednesday that police still don’t know if the shooting was random or targeted.

Castleton, in west-central Vermont, is about 5 miles east of the Vermont-New York border in an area known for scenic mountain views and slate and marble quarries. The university, founded in 1787 was closed last week for fall break. Students were excused from classes when it reopened Monday, and classes resumed Tuesday.