The Cat Who Smelled A Rat by Lilian Jackson Braun

October arrives in Moose County on the heels of a long drought, and the citizens of Pickax worry about wildfires. Their fears are realised in an unexpected manner, with a case of arson - and the shooting of a volunteer fire-watcher as he is reporting the blaze. The crime wave continues as the president of the curling club is pushed to his death down a flight of stairs, and it's up to Qwilleran and Co. to sniff out the rat who is responsible for it all.