(CNN) -- A young, beloved teacher found killed in the woods. A 14-year-old student in custody, charged with her murder.
That much we know. But hours after both were found -- one dead, one alive -- in suburbs northeast of Boston, much remains unknown as to why Colleen Ritzer died brutally.
"It is a terrible tragedy for the entire Danvers community," said Essex County District Attorney Jonathan Blodgett of the town some 20 miles north of Boston.
Authorities had been looking for the student, Philip Chism, first after he was reported missing -- with police sending out messages via Twitter and Facebook on Wednesday evening, noting he'd been last seen around 6:30 p.m. and asking for the public's help in finding him.
They got a call around 11:20 p.m. about another missing person, 24-year-old Ritzer, after she too hadn't returned home and was not answering her phone call, according to Blodgett.
A flurry of activity came next. Police in Topsfield, the town just north of Danvers, around 12:30 a.m. spotted Chism walking alongside a busy road there.
Authorities also converged on Danvers High School -- where Ritzer taught and which Chism attended -- finding blood in a second-floor bathroom, the district attorney said. The teacher's body was soon thereafter discovered behind the school.
Chism was tied to her death after police interviewed him and reviewed video surveillance from the school, a criminal complaint states.
"Based on his statements and the corroborating evidence found at multiple scenes at ... Danvers High School and surrounding wooded area, the juvenile was subsequently placed into custody and booked for murder," adds the complaint.
He was arraigned Wednesday afternoon in Salem, Massachusetts, on a murder charge, with prosecutors accusing him of beating the teacher to death. Afterward, Chism was ordered held without bail. A grand jury must decide if he will be charged as an adult.
Meanwhile, the tight-knit community of Danvers is at a loss to explain why someone might take the life of Ritzer, a 24-year-old known for posting inspirational messages on her Twitter account and offering students extra help when they needed it. All of Greater Boston, in various ways, is sharing in the pain: the Boston Red Sox plan to have a moment of silence Wednesday night before the start of Game 1 of the World Series at Fenway Park, according to club spokeswoman Zineb Curran.
All seven schools in the North Shore town were closed Wednesday, as investigators continued their work and students and residents mourned the loss of Ritzer.
"There's not words to describe her," freshman Spencer Wade said of Ritzer. "She's such an excellent teacher."
Suspect had lived in 3 states in recent years
Just Monday, the Danvers police department was tweeting its support for families and first responders affected by the shooting death of a Sparks, Nevada, teacher -- allegedly at the hands of a 12-year-old boy.
Little did these officers know they'd soon be investigating their own case of a student accused of killing a teacher.
While no motive has been spelled out in Ritzer's death, some details have started to emerge about the the young suspect.
Chism attended fourth grade at a Clarksville, Tennessee, elementary school, said Clarksville-Montgomery County, Tennessee, school system spokeswoman Elise Shelton. He then spent fifth grade at Hammock Pointe Elementary in Boca Raton, Florida, according to Palm Beach County school spokesman Owen Torres.
The next three years, he was back in Tennessee at Rossville Middle School in Clarksville, according to Shelton. Then his family moved about 1,150 miles northeast to Massachusetts.
Specifically, he was in Danvers, a town of about 26,000 people, and went to its lone public high school.
Blodgett declined Wednesday to discuss what connection, if any, he had with Ritzer.
When authorities first reported Chism missing Tuesday, people responded on the police department's Facebook page with prayers for his "safe return." One neighbor described him as "a polite and friendly boy."
The tenor of the comments changed significantly once he was linked to Ritzer's killing.
"I'd say he's less 'polite and friendly' than you thought," wrote one Facebook commenter. "Everybody has to keep their eyes open. It's no longer safe to say that you can take everybody at face value."
'The sweetest, most harmless person ever'
Ritzer had graduated from Assumption College in 2011, that school said on Twitter. She was pursuing a master's degree in school counseling at Salem State University, that school said in a prepared statement.
"As a dedicated teacher, Colleen wanted to work with and help children with special needs," an e-mail from the university read. "She believed children have much to offer and often do not realize how special they are as individuals. In her application to Salem State she said she was dedicated to 'helping students in times of need.'"
She was in her second year teaching at Danvers High, her aunt Shirley Martellucci said. Ritzer, who lived her parents, had never had any trouble with students, according to her aunt.
"She always wanted to be a teacher, all her life," Martellucci said. "It's just unbelievable that someone would take her life at such a young age."
On her Twitter account, Ritzer interspersed homework assignments and exhortations to work through tough math problems with cooking talk and inspirational messages.
"No matter what happens in life, be good to people," she wrote in August. "Being good to people is a wonderful legacy to leave behind."
Her family issued a statement seeking privacy as they mourn 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 the statement.
The district issued a statement Wednesday calling Ritzer "a dynamic and brilliant ray of light."
"Colleen Ritzer was everything one could ask for in a teacher -- dedicated, passionate and invested in her students. Our entire community will feel this loss for many years to come," the school said.
Ritzer's students were similarly dismayed.
Ritzer "was literally the sweetest, most harmless person ever," Twitter user samanthawxo posted Wednesday. "She always wanted to help anyone in any way she could."
CNN's Chandler Friedman, Stephanie Gallman, Alexis Weiss, Bob Crowley and Dana Garrett contributed to this report.