Prosecutors contend Chism, now 16, followed teacher Colleen Ritzer
, 24, into a girl's bathroom on the second floor of Danvers High School at 3:16 p.m. on October 22, 2013, and killed her.
The charges against Chism, who was 14 at the time of the crime, include aggravated rape and robbery.
Chism, who has pleaded not guilty, is being tried as an adult.
The defense team's case primarily focused on what it said was Chism's mental illness, arguing that he experienced a psychotic episode at the time of the crime.
At trial, family friends and classmates alike described Chism as a well-behaved, normal boy who grew quiet and began keeping to himself in the time leading up to Ritzer's slaying.
Dr. Anthony Jackson, testifying for the defense, said Chism's condition had improved after he was given anti-psychotic drugs following his arrest.
Another witness, Dr. Richard Dudley, who has met with Chism seven times, testified that the teenager heard voices and believed he was a ninja at the time of the homicide.
Dudley testified that Chism heard commanding voices that instructed him to carry out tasks, and that he had been on the schizophrenia spectrum since the age of 10.
Dudley also testified that Chism had expressed a level of remorse recently and believed that if he had not heard the voices he wouldn't have caused "difficulties" for Ritzer's family.
The prosecution challenged the medical testimony, accusing Chism of malingering, meaning that he fabricated or exaggerated his symptoms.
In the state's rebuttal, Dr. Nancy Hebben testified that Chism was not psychotic and showed multiple inconsistencies in his symptoms after a battery of tests. Chism had previously been found competent to stand trial.
Earlier at trial, the prosecution argued that Chism had planned the crime. Prosecutors showed the jury numerous surveillance tapes and crime scene photographs, including a video they said allegedly showed Chism following Ritzer into a school bathroom.
Photographs also showed Chism allegedly disposing of Ritzer's body in a recycling bin, prosecutors said. Jurors also visited numerous locations associated with the crime, including Danvers High School.
Surveillance photos showed the then-14-year-old outside the school, wheeling the recycling bin prosecutors say held the body of his slain algebra teacher.
Images introduced in court showed Chism wearing a white T-shirt and blue jeans and carrying a red sweatshirt that he was seen wearing later. He left the school with the recycling bin at 3:23 p.m., according to prosecutors.
Photos allegedly show Chism outside the girl's bathroom, barefoot with blood on his hands and jeans. After he's seen walking outside with the recycling bin, cameras later caught Chism in the school in a black sweatshirt, black shorts, and blue sneakers, and prosecutors allege he changed clothes in a bathroom on the third floor.
Photos showed what prosecutors described as Chism taking the recycling bin into the bathroom with a balaclava around his neck, then subsequently walking out with the balaclava over his face.
Prosecutors say at least one other security video implicates Chism. Footage captured at the AMC Theater in Danvers on the day that Ritzer died shows a person prosecutors identified as Chism purchasing tickets for "Gravity."
Lida Parsons, the theater's general manager, testified the name on the credit card receipt was that of Colleen Ritzer.
Several items of clothing were placed into evidence, and Abbey Scott with the Massachusetts State Police Crime Laboratory testified that a black sweatshirt, a pair of jeans, a white T-shirt, a red sweatshirt, a pair of dark green women's underwear and a pair of white gloves found in the woods outside the school all tested positive for blood. A reddish-brown stain on Chism's left hand as well as brown stains on a box cutter also tested positive for blood, Scott said.
"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.
Sarah Giaquinta, a co-worker of Ritzer's, testified that she had spoken with Ritzer on the afternoon of her death. After classes had finished for the day, the two met in Ritzer's classroom, where Giaquinta saw two of Ritzer's students.
Giaquinta said that while the conversation was normal, Ritzer had mentioned that she "didn't know why the boy [was] here" after school hours. Giaquinta identified that boy as Chism.
Judge David Lowy told jurors that they should expect to receive the case for deliberations either Thursday or Friday.