The Cat Who Wasn't There (Cat Who..., #14)

an alternate cover edition can be found here

Qwill's on his way to Scotland - and on his way to solving another purr-plexing mystery. But this time Koko's nowhere the scene of the crime. He and Yum Yum are back in Pickax being coddled by a catsitter...but Koko won't sit still once Qwill's traveling party returns--minus one member. He's behaving oddly, and Qwill knows what that means: Koko may have been miles away from the murder scene, but he's just a whisker away from cracking the case!