Authorities have not released the name of the suspect, but two people who saw him taken into custody say he is 16-year-old Chris Plaskon.
Plaskon is charged with murder as a juvenile offender in Friday's slaying of fellow student Maren Sanchez at Jonathan Law High School in Milford. An attorney for Plaskon says his client is under psychiatric evaluation.
Teacher Mark Robinson says he coached Plaskon in football for two years and describes him as funny and from a family with deep roots in the community.
Student Imani Langston says Plaskon is known for being a class clown.