This is the chilling last moment of a teacher that was gruesomely murdered at the very school she worked at. It seems like with the trend of police hate, no civil servants are safe any longer.

(FOX) BOSTON — Surveillance video shows Philip Chism, a former Massachusetts high school student accused of raping and killing his algebra teacher, following the woman moments before her slaying.

In the video that was presented as evidence in court Wednesday, the then-14-year-old Chism follows Colleen Ritzer in the hallway of Danvers High School on Oct. 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.

He is accused of killing Ritzer, 24, with a box cutter in a girls’ bathroom at the school. Chism, now 16,  pleaded not guilty to aggravated rape, robbery and murder charges in January. He is being tried as an adult.

Read more: Fox 4 KC