Quad

Now six students, from six different cliques, are trapped in the student store while a shooter terrorizes their school. The shooter's identity is teased out through the students' flashbacks until the reader breathlessly reaches the final page. It's only there that he discovers the shocking answer to the question: Who is shooting out in the quad?

This gripping thriller by educator C. G. Watson is inspired by observations made in her own high school. Quad examines in heartrending detail how even the most casual cruelties can tear people apart."

Summary from publisher Razorbill, available through the Library of Congress catalog:

http://catdir.loc.gov/catdir/enhancements/fy0743/2007001858-d.html