The trial of a teenager accused of raping and murdering his 9th grade math teacher is headed to trial as jury selection is set to begin on Wednesday in Salem District Court. 

Philip Chism plead not guilty to raping and murdering 24-year-old Colleen Ritzer, a math teacher who was found dead in the woods near Danvers High School on October 23, 2013.

She had been raped and her throat was slashed open with box cutter, according to authorities.

According to authorities who found Ritzer's body in the woods near the school, the note next to her body read, “I hate you all.” 

RELATED: Philip Chism: Danvers High School teacher Colleen Ritzer murdered, 14-year-old charged

Investigators said Ritzer had asked Chism to stay after class on Oct. 22nd.

Chism was seen on video surveillance footage following Ritzer to the bathroom, where the initial attack began. Prosecutors said the footage shows Chism go into the bathroom wearing gloves and a hood and walks out alone about 12 minutes later. He was then seen pushing a recycling barrel in the hallway and outside. The barrel was found near her body. Authorities say she was sexually assaulted twice, once with a stick. 

Police found Chism walking along Route 1 in Topsfield with a bloody box cutter in his backpack, along with a pair of women’s underwear and Ritzer’s identification. 

Defense attorneys said they plan to use the boy’s mental health as a defense. They have recruited Dr. Richard Dudley, a well-known forensic scientist, to testify and offer expert analysis. 

Chism had also been charged with attempted murder by strangulation, assault with intent to murder and assault and battery with a dangerous weapon after he is said to have attacked a female clinician at the facility he was being held.

RELATED: DA: Philip Chism punched, choked, stabbed female DYS worker

He was 15 at the time of that attack.