Sources: Teen followed Danvers teacher into bathroom, killed her with box cutter

Danvers High School teacher Colleen Ritzer is seen in this undated photo provided by the family of Ritzer. (AP Photo/Courtesy of Dale Webster via the Lawrence Eagle-Tribune)

(CNN) -- How was Danvers High math teacher Colleen Ritzer killed? With a box cutter the 14-year-old suspect had brought into school, a source close to the investigation says.

What happened to her body afterward? It was stashed in a recycling bin, rolled outside, then dumped about 20 feet into woods behind the northeastern Massachusetts high school's athletic fields, adds another source. It was left there -- not buried, not even covered.

And where did the alleged killer go afterward? After changing his clothes, he went to a Wendy's fast food restaurant and a movie, sources say, before police in a neighboring town saw him walking on a busy road under the pitch-dark sky early Wednesday.

Those are the answers, many of them revealed Thursday, two days after the teacher's killing. Yet the question of why this happened -- why a popular young educator who always wore a smile and went the extra mile was killed allegedly by a teenager who friends, family and co-workers described as reserved and well-behaved -- continues to loom large.

The suspect, had recently had moved some 1,150 miles from Clarksville, Tennessee, to the Boston suburb of Danvers before the start of this school year, remained jailed without bond Thursday. A grand jury will play a big part in deciding his next step: If they indict him for first- or second-degree murder, he -- like any juvenile age 14 or older -- would be tried as an adult, based on Massachusetts law.

Meanwhile, the tight-knit North Shore community is still trying to make sense of what he allegedly did and of life without a teacher who so many appreciated, learned from and loved.

"It's just surreal how quickly someone can go, and how much we take for granted every day," said Danvers High student Chris Weimert. "(Ritzer was) he nicest teacher you could ever have. I can't believe it."

2 missing persons' reports come together

Students and colleagues described the 24-year-old Ritzer as someone who gave everything for her students -- be it a pat on the back, a sensible explanation to a tricky concept, or the time, effort and heart to work through problems, math or otherwise, with them.

One of those students was the suspect, a freshman.

After school on Tuesday, Ritzer had gone to a regular students' girls bathroom on Danver High's second floor, as someone was in the locked faculty bathroom, a source close to the investigation said.

This bathroom wasn't locked. The suspect allegedly followed her in.

There, Ritzer was punched a few times before being killed with a box cutter around 3:30 p.m., said a source.

Her body went into a recycling bin, then outside the school where it was tossed. Authorities eventually found a bin that apparently had been thrown off an embankment some 100 feet away from Ritzer's body, a source said.

Before police found her -- before they even knew she was missing -- they'd started looking for missing suspect.

This was in the early evening, with Danvers Police tweeting to residents that he hadn't returned home and was last seen around the Hollywood Hits movie theater in the town some 20 miles northeast of Boston.

While they were looking for him, police got a call around 11:20 p.m. Tuesday about another missing person: Ritzer. She wasn't home either, nor had she answered her phones.

The stories started coming together about an hour later, when police officers in nearby Topsfield found the suspect walking along Route 1.

Whatever he told detectives in his subsequent interviews, whatever they saw in surveillance footage from the school, led to suspect's arrest for murder. It also led them to Ritzer's dead body in the woods.