The Cat Who Saw Stars (Cat Who... #21)

an alternate cover edition can be found here

UFOs in Mooseville? Rumors abound that a missing backpacker has been abducted, and it looks like Jim Qwilleran's sedate summer may be interrupted by an investigation -- with the help of his own little aliens, Koko and Yum Yum. And when the backpacker's body turns up -- and transplanted Floridian Owen Bowen is found dead soon afterward -- the search for intelligent life turns into a close encounter with a killer...