The Case of the Canny Killer, by Harry Stephen Keeler (epub/Kindle/pdf)
America's war effort is being threatened by sabotage at the Tippindale Steel Plant, and Superintendent Noah Turnbo has got to stop it! His main suspect is Kel Lauriston, a boomer, but Kel has other things than sabotage on his mind -- like getting married. Unfortunately for him, Plant Foreman Red McAfee is in love with the same girl, too. Throw in a patch of catnip down by the plant fence, a pack of Chinese laundrymen, and a powerful telescope, and you have a webwork mystery that only Harry Stephen Keeler could unravel!