WINDHAM — The mood was mostly positive and confident Thursday morning as students and staff members returned to classes in Regional School Unit 14 after emailed threats shut down public schools in Windham and Raymond for three days.

Police have charged Justin Woodbury, 16, of Windham, with felony terrorizing in connection with emails sent to two school administrators Monday morning in which he threatened to use weapons, police said. The teen’s father, John Woodbury, said his son left Windham schools two years ago to attend Baxter Academy, a charter school in Portland. The boy is awaiting a Jan. 8 arraignment at the Long Creek Youth Development Center in South Portland.

“I’m feeling OK,” said sophomore Dominic Stevens as he entered Windham High School shortly after 7 a.m. “I’m not worried at all. I feel confident they got the only guy involved.”

Kevin Roy, a student teacher from the University of Southern Maine, said he expected students and staff to transition easily back into their routines, but he acknowledged that the threats generated some fear and anxiety.

“I’m glad to be back and return to some sense of normalcy,” Roy said. “School is expected to be a safe place. To have someone threaten that is upsetting.”

Tayla Fortin, a senior, said she returned to classes Thursday feeling unsettled. That someone threatened to harm students “was a scary, scary thought,” she said.

Parents expressed appreciation for the way school and police officials handled the threats, sending students home Monday morning and keeping parents informed throughout the investigation.

“I’m just pleased that school officials put the students first,” said Judith MacDonald, as she dropped off her grandson Caleb MacDonald, a sophomore.

“It truly was a community effort to take care of the situation,” said Windham High Principal Christopher Howell. “It was nice to say, ‘Welcome back’ to the kids this morning.”

During morning announcements, Howell told students that counselors were on hand to talk with anyone who might be feeling uncomfortable. He urged students to avoid wasting time on rumors and theories and assured them they would be safe.

“We will return to business as usual,” Howell said. “We will still celebrate tomorrow with our annual holiday assembly, and we will be the loudest, proudest, ugliest-sweater wearing group that Windham High School has ever seen. Let’s take back our school and make these next two days fantastic.”

Jeff Smith, the school resource officer from the Windham Police Department, looked on as students and staff entered the high school Thursday morning.

“This affected two entire communities,” Smith said of the emailed threats and the shutdown that affected eight public schools. Widespread impacts ranged from the inconvenience experienced by parents who had to scramble to find day care to the fear felt by extended families and others throughout southern Maine.

Smith is part of the police presence that will be maintained at each school for the rest of the week to ensure that students feel comfortable, Superintendent Sandy Prince said Wednesday.