King & Kayla and the Case of the Secret Code - Dori Hillestad Butler

The first in a new series featuring King, a lovable dog who helps his girl Kayla solve the mystery of who sent letters, written in code, to Kayla and her friend, Mason. Full color. A lovable dog helps his human girl solve a mystery. Kayla and Mason both got mysterious letters, written in code. What does Kayla know? --The same person left both letters. It's someone she and Mason both know. The two letters are the same, except for the second word.What does King know? --Jillian left the letters. What do the letters say?