Tails of Mystery: Book 1 of Fred, Joe, Kitkit, Cat, & Co.

Fred might be a German Shepherd, and Joe is probably a Chihuahua. The mysteries they investigate range from exploding houses to waste bins and laundry baskets. Squirrels, cats and raccoons are their traditional enemies of course, but who knows what strange friendships they'll form as they wag their tails and solve all the mysteries they can find.