I read a few and saw a few movies that tell me otherwise... Discussing an hypothetical "perfect murder"... Detailing how they were murdered with a frozen icicle so there won't be any weapon or fingerprints left...
I mean those examples are a bit exaggerated. But there are pretty realistic stories. And I'd say the lines between story and guide aren't always that clear. That's part of the thrill. The good ones are kinda detailed enough to be both.
Same goes for historical records.
And I think if you grow up completely sheltered from evil and true life, you're bound to miss out, not to know aboud bad things. You won't have any understanding or defense against it and will get exploited. And you're missing half of the fun and intelligence that would otherwise be your potential. Also you can't keep kids from having to make their own decisions forever. At some point they need the tools and knowledge to decide for themselves.
I can recommend the sci-fi dystopia "The Giver" about that. (The sheltering part, not the murder mysteries.) But read the book, the movie isn't good at all. And read it while you're young, it's probably more suited for adolescents than for adults.