Philip Chism, 14, held without bail in Danvers High School teacher Colleen ...

DANVERS, Mass. A 14-year-old high school student described by classmates as soft-spoken and pleasant was accused of killing a well-liked math teacher, whose body was found in the woods behind the school.

Law enforcement officials recovered the remains of 24-year-old Danvers High School teacher Colleen Ritzer early Wednesday, Essex District Attorney Jonathan Blodgett said. The teen, Philip Chism, was arraigned Wednesday in Salem on a murder charge and ordered held without bail.

Ritzer was reported missing late Tuesday night after she didn't come home from work or answer her cellphone. Investigators found blood in a second-floor school bathroom and soon located her body, Blodgett said. He did not say how Ritzer died.

'She was a very, very respected, loved teacher,' Blodgett said, calling the killing a 'terrible tragedy.'

The boy also was reported missing Tuesday after not coming home from school. He was spotted walking along a road in neighboring Topsfield at about 12:30 a.m. Wednesday.

Investigators said in court documents that the arrest was made based on statements by the suspect and corroborating evidence at multiple scenes. They said they also recovered video surveillance.

At his arraignment in adult court Wednesday afternoon, Chism's defense attorney argued for the proceeding to be closed and her client to be allowed to stay hidden because of his age. The judge denied the request. The attorney declined to comment outside court.

Ritzer had a Twitter account where she gave homework assignments, encouraged students and described herself as a 'math teacher often too excited about the topics I'm teaching.'

She was a 2011 graduate of Assumption College in Worcester, a school spokeswoman said Wednesday. She graduated magna cum laude with a bachelor of arts degree in math, a minor in psychology and a secondary education concentration, according to the college's 2011 commencement program.

'I just remember seeing her in the hallway and she always had a smile, like 'hi' to everyone, and she was just an amazing person,' Megan Papagelis, a Danvers High graduate, told CBS Boston station WBZ-AM.

'It's just shocking to see that this could happen,' Papagelis told WBZ-AM. 'Unbelievable.'

Chris Weimert, 17, was a student in Ritzer's geometry class last year. He told news3blog.blogspot.com that she had taught at the school for two years and was a warm, welcoming person who would stand outside her classroom and say hello to students she didn't teach.

'She was the nicest teacher anyone could ever have. She always had a warm smile on her face,' he said.

Weimert said the suspect, who he knew from seeing him around school, 'seemed like a good kid.' He said, 'It really threw the whole town of Danvers a curve ball.'

Kyle Cahill, a junior, told the AP he knows Chism from the soccer team. He said the 14-year-old moved to Massachusetts from Tennessee before the school year began and was a top goal scorer on the school's junior varsity team.

He called him a quiet, nice kid.

'He wasn't violent at all. He was really the opposite of aggressive,' Cahill said.

Cahill said there was a soccer team dinner Tuesday night that the accused teen skipped, and team members were wondering where he was.

'We're all just a family. It just amazes me really,' he said. 'I'm just stunned.'

Ryan Kelleher, a senior who also plays soccer, said the arrest of the soft-spoken Chism didn't make sense to him.

'From what I know about him and seeing him every day, it just doesn't add up that he would do such a thing, unless this was all an act to fool somebody,' the 17-year-old said.

Kelleher took Ritzer's algebra class last year and said hello to her on Tuesday in the hallway. He said students related to the young teacher, who liked to wear jeans and UGG boots just like the students.

Ritzer lived at home with her 20-year-old brother and her sister, a high school senior. The close-knit family was often outside, barbecuing, spending time together and enjoying each other's company, neighbors said.

Mary Duffy has lived next door to the Ritzers in the comfortable, suburban neighborhood in Andover since the family moved there more than two decades ago. She had known Colleen Ritzer from the time she was a baby and said the Ritzers' oldest child had just one ambition in life: to be a high school math teacher.

'All I ever heard is that she loved her job,' Duffy said.

Ritzer's uncle Dale Webster provided a brief written statement in which the family asked for privacy.

'At this time, we are mourning the tragic death or our amazing, beautiful daughter and sister,' the statement read. 'Everyone that knew and loved Colleen knew of her passion for teaching and how she mentored each and every one of her students.'

There was no reason to believe anyone else was involved and there was no public safety danger, authorities said.

All public schools in Danvers, about 20 miles north of Boston, were closed Wednesday.

The high school's students were planning a candlelight vigil Wednesday evening.

Ritzer is the second teacher allegedly killed by a student in the U.S. this week. A Sparks, Nev., middle school teacher was allegedly shot by a 12-year-old student on Monday.