HIGH SCHOOL SHOOTING SHOCKS MANHATTAN; CAREY LOWELL GUEST-STARS -- When a masked student opens fire on classmates, killing four and wounding eleven, Detectives Briscoe (Jerry Orbach) and Green (Jessie L. Martin) soon discover the unsettling fact that more than one student fits the profile of a youth heading toward committing such violence. The urgency of the investigation compounds when an e-mail threat of more murders is received by the student council president. Carey Lowell returns in a guest appearance as defense attorney Jamie Ross, who tries to spare her troubled client from life in prison. Sam Waterston, Angie Harmon, Dianne Wiest and S. Epatha Merkerson also star.