Philip Chism in new video following Colleen Ritzer 'before raping and murdering her'

Chilling new surveillance video showing a high school teacher's last moments of life was played in court Wednesday during the trial of the teen accused of raping and murdering her.

Jurors watched video in court from the surveillance cameras at Danvers High School, Massachusetts, that caught what prosecutors say is Philip Chism, then 14, following Colleen Ritzer in the hallway.

Chism, now 16, has pleaded not guilty to murder, rape and other charges in the October 2013 slaying of 24-year-old Ritzer, a math teacher at the high school.

The video first shows Ritzer, sporting a smile and a purple top with black pants as she waves to someone who isn't on camera, walking alone down a hallway at the school.

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