Students at Danvers High School in Massachusetts have returned to class just two days after beloved math teacher Colleen Ritzer was brutally killed, USA TODAY reported.

Ritzer, 24, died after being attacked by student Philip Chism, 14, who was charged with murder on Wednesday.

As the school reopened, the American flag was held at half-staff and trees were decorated with pink ribbons in honor of Ritzer, whose favorite color was pink.

In addition, an electric sign read one of her favorite sayings -- "No matter what happens in life, be good to people. Being good to people is a wonderful legacy to leave behind."

A car in the school's parking lot also had a message honoring Ritzer written in their blue and white school colors: "RIP Miss Ritzer. Gone, not forgotten."

During a meeting Thursday night, police and school officials notified parents that extra safety precautions would be performed in order to reassure students, including locked side doors, additional officers, and extra counselors on hand if needed.

Rabih Chaghouri, whose daughter is a freshman at the school, said he isn't concerned for the students' safety.

"This could happen in any neighborhood, any street, anywhere. You never know what goes on in people's heads," Chaghouri said.

Carrie Kimball-Monahan, a spokeswoman for the prosecutor's office, said the case is in the middle of being investigated and has not offered a possible motive behind the attack.

According to student Rania Rhaddaoui, Ritzer caught Chism doodling in his notebook instead of taking notes during the Algebra I class she was teaching and asked him to stay after class.

After Ritzer never returned home and blood was found in a school bathroom, officials began a searching leading to her body, dumped in a wooded area behind the school. 

Officials believe she was killed around 2:00 p.m., right after school ended.Students at Danvers High School in Massachusetts have returned to class just two days after beloved math teacher Colleen Ritzer was brutally killed, USA TODAY reported.

Ritzer, 24, died after being attacked by student Philip Chism, 14, who was charged with murder on Wednesday.

As the school reopened, the American flag was held at half-staff and trees were decorated with pink ribbons in honor of Ritzer, whose favorite color was pink.

In addition, an electric sign read one of her favorite sayings -- "No matter what happens in life, be good to people. Being good to people is a wonderful legacy to leave behind."

A car in the school's parking lot also had a message honoring Ritzer written in their blue and white school colors: "RIP Miss Ritzer. Gone, not forgotten."

During a meeting Thursday night, police and school officials notified parents that extra safety precautions would be performed in order to reassure students, including locked side doors, additional officers, and extra counselors on hand if needed.

Rabih Chaghouri, whose daughter is a freshman at the school, said he isn't concerned for the students' safety.

"This could happen in any neighborhood, any street, anywhere. You never know what goes on in people's heads," Chaghouri said.

Carrie Kimball-Monahan, a spokeswoman for the prosecutor's office, said the case is in the middle of being investigated and has not offered a possible motive behind the attack.

According to student Rania Rhaddaoui, Ritzer caught Chism doodling in his notebook instead of taking notes during the Algebra I class she was teaching and asked him to stay after class.

After Ritzer never returned home and blood was found in a school bathroom, officials began a searching leading to her body, dumped in a wooded area behind the school. 

Officials believe she was killed around 2:00 p.m., right after school ended.