Colleen Ritzer, 24, a math teacher at Danvers High School in Massachusetts, was reported missing Tuesday after failing to return home or answer her cell phone.
Philip Chism, 14, appeared in court Wednesday, charged with assaulting, beating and murdering her.
He was ordered held without bail and would be tried as an adult, said a spokeswoman for the district attorney.
Police discovered blood in the second floor bathroom of the Danvers High School and found her body in nearby woods, said Essex District Attorney Jonathan Blodgett.
“It was apparent that she is a homicide victim. She was a teacher here at Danvers High School. This is a terrible tragedy,” he told a news conference.
Chism was picked up police while walking north along a highway in the early hours.
The teen had not returned home after school on Tuesday and had been reported missing to police.
Danvers is a small town half an hour’s drive north of Boston. Public schools were closed there on Wednesday.
On Monday, a 12-year-old boy fatally shot dead a math teacher and critically wounded two students at a school in the US state of Nevada.
Michael Landsberry, a 45-year-old former Marine who had served in Afghanistan, was killed after confronting the young shooter, allowing other students to flee.
The boy then took his own life by turning his 9 mm semi-automatic handgun on himself at the Sparks Middle School in Reno.