Isso é um palpite, mas que tal " Eu sempre faço o que Teddy diz " de Harry Harrison. Descrição sorta se encaixa:
"the name of an old (70's maybe?) sci fi story about a future where children are raised by teddy bears - the teddy bears are kind of like "skinner boxes" they provide all of the moral and social training that children need to become positive, functioning citizens. the protagonist in the story has killed a politician but can't reconcile his action because it should be impossible- all teddy bears are programmed to teach that murder is wrong, ergo murder has ceased to exist. the denouement happens when he questions his teddy bear about murder and his teddy bear is silent- he realizes that he has been groomed from birth to be a political assassin - his teddy bear was programmed without this crucial information"