Jim (I won't try to spell his last name, I'd have to copy paste it) and his 2 cats. Though he doesn't get his 2nd cat till book 2 or 3. Jim starts out working for a newspaper in a large city, having been a alcoholic for years and luckily when he now wants to straighten out his life a friend of his is an editor for a newspaper in the large town. He solves murders, mostly it's his cat koko who gives him clues and most of the time he's as much of a dunce at missing them as Jimmy and Lois are at not noticing that clark looks exactly like superman except he has on glasses. It seems koko is a very smart cat and a bit psychic maybe, with Jim having bits now and then, supposedly all tied to his mustache, or koko having more whiskers then normal cats.
He does eventually piece the clues together. Often the books have odd background characters. & once Jim moves up north in the 5th book then often keep the same odd background characters instead of having new ones with every book.
So I thought why not mention them.
No non humans in the book, unlike Anonymous Rex and the prequel I've not read.