From the back cover of the Del Rey first edition: Who was the cop killer? A Silent? Their anger launched the crime wave that brought the Terrans to Egar. Could one of them be ruthless enough to want the police out of the way - permanently? A Normal? The telepathic aliens seemed friendly enough - but psychotics could fake innocence. And if their culture permitted murderous conspiracy - how would the humans know? A Terran? Faced with culture shock on a strange world - their innermost thoughts open to the mind readers - fears and pressures mounted. Had one of their own gone mad? As the cops tried to solve the mystery, somewhere the assassin waited...
Source · ISFDB CC BY 4.0
