Reddit mentions of The Immortals Boxed Set (Wild Magic + Wolf-Speaker + Emperor Mage + The Realms of the Gods)

The Enchanted Forest series by Patricia C Wrede is engaging, witty, and sex-free.

The Book Thief by Marcus Zusak is wonderful for everyone of any age. It has lyrical writing, a story that sticks with you, and moving imagery. I can't recommend it enough.

Tamora Pierce's Tortall novels are great (I'd recommend starting with the Protector of the Small series or The Immortals series). There is some sex in them, but it's not graphic and it's far from the focus of the books.

The Bartimaeus Trilogy by Jonathon Stroud is witty, well-paced, and engaging.

The Sabriel series by Garth Nix is pretty dark, but no more so than the ones you listed.

Let us know what you end up getting her!

I've just been re-watching these as well :)

These aren't detective stories, but if you want strong capable heroines, I'd recommend Tamora Pierce's books, particularly:

[Tricksters] (http://www.amazon.com/Tricksters-Daughter-Lioness-Tamora-Pierce/dp/0739451456/ref=sr_1_2?s=books&ie=UTF8&qid=1334468727&sr=1-2) series

This heroine, Aly, has the most in common with Veronica (in terms of wit, slight cynicism, talents)

But also:
[The Song of the Lioness] (http://www.amazon.com/The-Song-Lioness-Quartet-Adventure/dp/0375825649) series
[The Immortals] (http://www.amazon.com/Immortals-Boxed-Wolf-Speaker-Emperor-Realms/dp/0375827005/ref=sr_1_4?s=books&ie=UTF8&qid=1334468603&sr=1-4) series
[Protector of the Small] (http://www.amazon.com/Protector-Small-First-Squire-Knight/dp/0739446983/ref=sr_1_8?s=books&ie=UTF8&qid=1334468653&sr=1-8) series