Books with title Trixie Belden and The Mystery in Arizona

Trixie Belden and the Black Jacket Mystery. There was a small branch lying at one side. It was only about twenty inches long, and someone had cut all the side twigs off it. Trixie picked it up, curious as usual. It came from a crab-apple tree. There was a dark stain on the heavy end of the piece of wood. And caught in the grain of the wood was a small tuft of gray hair. The stain could only be blood....

In Trixie Belden and the Gatehouse Mystery, the third book in the Trixie Belden series, when Trixie, Honey, and Bobby go exploring an old gatehouse, Bobby stumbles and cuts his knee on a large diamond. Honey and Trixie decide to solve the mystery of the diamond themselves with the help of Jim and Trixie's brothers, Brian and Mart. They have two suspects, the Wheeler's new chauffeur and the gardener. Trixie's convinced she knows who the diamond thief is, but what will it take to convince the others, and will she be able to save Jim from the thief?