Cam Jansen and the Mystery of the Stolen Diamonds (1980)
Cam Jansen and the Mystery of the Stolen Diamonds is a 1980 detective and mystery stories book written by David A. Adler.
Cam and Eric are sitting in the mall when an alarm goes off and a man races out of a jewelry store. When the police arrest the wrong person, it's up to Cam and Eric to catch the real thief.