BOSTON - A 14-year-old student at a suburban high school outside Boston was in custody Wednesday after police found the body of a teacher in the woods behind the school overnight, officials said.

Police in Danvers, Massachusetts, began an investigation late on Tuesday after receiving calls that a student at the school had not returned home, and that a teacher had also not gone home and was not responding to her cell phone, Essex County District Attorney Jonathan Blodgett told reporters on Wednesday.

Police found the body of Colleen Ritzer, 24, a math teacher at Danvers High School, in the woods after discovering blood in a second-floor bathroom.

"It was apparent that she was a homicide victim," Blodgett said. "This is a terrible tragedy."

Blodgett declined to identify the suspect, who was taken into custody, because he is a minor.

The student, who was found walking along a highway about 12:30 a.m. EDT (0430 GMT), was due to make a court appearance later on Wednesday in a session closed to the public.

Danvers police on Tuesday had issued a missing-child report on a 14-year-old male whom they said had been located early on Wednesday.

All public schools in Danvers, about 20 miles (32 km) north of Boston, were closed on Wednesday, although police believed there was no continuing threat to public safety.

"We have no reason to believe there were any other suspects involved," Blodgett said.

Blodgett declined to comment on how Ritzer was killed or if there might have been any type of relationship with the student.

The incident is the second murder at a U.S. school this week. On Monday, a 12-year-old boy shot a teacher to death and wounded two fellow students at his Nevada middle school.