The video, shown to jurors as evidence in court Wednesday, shows the then-14-year-old Chism following Colleen Ritzer
in the hallway of Danvers High School on October 22, 2013.
Chism, wearing a hooded jacket that partially obscures his face, follows her as she walks alone down the hallway. Ritzer does not seem to be alarmed, and even raises her hand to wave at an unseen person in the hallway. The video cuts to a shot of Ritzer walking into the bathroom. Chism, a few steps behind, pauses at the door and puts on gloves before walking in behind her.
Chism is accused of killing Ritzer, 24, with a box cutter in a girls' bathroom at the school. Chism, now 16, has pleaded not guilty
to aggravated rape, robbery and murder charges in January. He is being tried as an adult.
In court Wednesday, jurors also viewed the recycling bin that Chism allegedly used to move Ritzer's body to the woods where she was found a day later, according to Carrie Kimball-Monahan, director of communications for Essex County District Attorney's Office.
Ritzer's throat was slashed and she had been raped with an object, authorities have said. A handwritten note found next to her body read "I hate you all," according to court documents.
While the defense has acknowledged that Chism committed the crime, they claim he was having a psychotic episode when it occurred. Earlier this month, he was found competent to stand trial.
"He was severely mentally ill," said Chism's attorney, Denise Regan, during her opening statement Monday. "He had been suffering from a psychiatric disorder since the age of 10."
But prosecutors argue it was a premeditated crime.
"When 14-year-old Philip Chism arrived at Danvers High School, he had in his possession a blue sweatshirt with a hood, gloves, a mask, a box cutter, and a terrible purpose," prosecutor Kate MacDougall said in her opening statement.
Chism became "visibly upset" after Ritzer
spoke about his home state of Tennessee after class, another student said, according to a police affidavit.
More surveillance video from both inside and outside the school will be shown during the court proceedings in coming days, according to Kimball-Monahan.