US teacher Colleen Ritzer was 'killed with box cutter'

Parents and students held a vigil at Danvers High School on Wednesday

A student accused of murdering a Massachusetts high school maths teacher used a box cutter to stab her before disposing of her body, US media report.

Philip Chism, 14, was charged on Wednesday as an adult over the death of Colleen Ritzer, 24, whose body was found in woods behind the school.
The Boston Globe reports that school CCTV cameras showed the accused pushing a recycling bin through the building.
It is not known if Ritzer's body was inside.
She was found dead in woods behind the school, after being reported missing late on Tuesday.
Danvers High School, in a suburb of Boston, reopened on Thursday for students to speak to counsellors. Classes will resume on Friday.
'Amazing, beautiful daughter' Officials said Ritzer and the suspect knew each other from the school, but did not elaborate.

Colleen Ritzer reportedly lived in her family home with her younger siblings

Gardner Trask, chairman of the Danvers Board of Selectmen, told the Associated Press news agency the killing is a "devastating blow" to the close-knit town.
On Wednesday evening the Boston Red Sox held a moment of silence for Ritzer before the first game of the World Series, America's professional baseball championship.
And hundreds of people attended a candlelit vigil at the school's car park, wearing pink clothes or bows in tribute to Ritzer's favourite colour.
Ritzer reportedly lived in her family home with her younger brother and sister.
Her family said they were mourning the death of their "amazing, beautiful daughter and sister".
"Everyone that knew and loved Colleen knew of her passion for teaching and how she mentored each and every one of her students," the family said in a statement.
'Opposite of aggressive' Ritzer was said to be friendly towards the school's students, many of whom were not much younger than her.

Philip Chism was arraigned in Salem District Court on Wednesday

Her Twitter biography describes the maths teacher as "often too excited about the topics I'm teaching". She used the account to set homework for students.
The suspect's family and lawyer have not spoken to reporters.
The accused had moved to Massachusetts from the state of Tennessee before the start of the school year.
He was said to be a star player on the school soccer team. One student, Kyle Cahill, told the Associated Press the suspect's absence had been noted at a team dinner on Tuesday night.
"We're all just a family. It just amazes me really," said Kyle. "He wasn't violent at all. He was really the opposite of aggressive."
Ritzer's death is the latest incident this week to send police scrambling to a US school:

• On Wednesday an 11-year-old in the north-western state of Washington was charged with attempted murder after bringing 400 rounds of ammunition, a handgun and several knives to his school
• A teacher was killed on Tuesday in Sparks, Nevada, by a 12-year-old boy who then turned the firearm on himself. Two other students were wounded in the shooting

A Gallup poll released on Wednesday suggested that 25% of US parents are concerned about their children being harmed while at school, making it one of their top crime concerns.