Hold tight, by Harlan Coben

Tia and Mike Baye have a 16-year-old son, Adam. Adam's good friend Spencer committed suicide and Adam has been despondent ever since. Adam's parents decide they need to find out more about what Adam is doing, so they purchase a computer program that lets them into his computer. They find a suspicious message, and then Adam disappears. Tightly written, fast-paced look at a typical family concern: do teens have a right of privacy?