Khayell Dupree, 12 – a 7th grader at nearby Mott Hall Bridges Academy – was walking home from school when another boy his own age knifed him inside Betsy Head Park in Brownsville minutes before 3 p.m., according to cops and the middle schooler’s mom.

Federick Green cut "an extensive amount" of his hair off to try to conceal his identity, changed his phone device, and deactivated his social media accounts after the shooting, prosecutors said.