Waverly Curtis - The Big Chihuahua /A Chihuahua in Every Stocking (Barking Detective Mystery #3/ #3.5)

P.I. Geri Sullivan and her talking Chihuahua, Pepe, are always hungry to sink their teeth into a new case. So if helping a hapless husband win back his wayward wife means sneaking into a cult of dog-worshippers, porque no?
Inside the believers' rural retreat, Pepe perks up his ears when the charismatic leader pegs him as the next incarnation of the spirit Dogawanda. But the discovery of a body, murdered between mantras, suggests there's more chicanery than channelling going on in this suspicious sect. While wild wolves howl, a killer is on the prowl—and it's up to Geri and her canine compadre to dig up the dirt.

Bonus short story A Chihuahua in Every Stocking
Who would steal a little girl's dog, right before Christmas? After seeing young Sophie's heartbreaking story on the news, P.I. Geri Sullivan and Pepe—her talking Chihuahua—vow to rescue this bonita canine named Chiquita. But tracking the pooch's scent through a Pacific Northwest winter wonderland isn't easy, especially when the trail leads to an elf that's been mortally mauled! Geri and Pepe must save little Sophie's Christmas and find this muy naughty dognapper . . . and stir up a little Christmas magic along the way!