Cat Spitting Mad by Shirley Rousseau Murphy (2001, Paperback, Reprint)

While Joe Grey has played tricks on Max Harper, Molena Points head lawman, he's never had anything but respect for the dedicated sheriff. Now Harper's in trouble, suspected of murdering two friends, and the only witness, a young girl named Dillon, has disappeared. Both Dulcie and Joe know Harper is innocent, and Joe is hissing to prove it -- and find Dillon. Their sleuthing, however, is hampered by something soft and small -- their new "ward," a vivacious kitten whose curiosity could get them all killed. With backs up and claws bared, Dulcie and a spitting mad Joe must use all their cleverness and amazing talents not only to find a killer, save a little girl, and clear their friend's name -- but keep their secret safe, too.