Death in Disguise
Published in Operator #5 #13, April 1935
"Captain John Vedders played a dangerous game in that brilliant mansion - against the most beautiful and wicked woman spy in the world — in an effort to leash the brutal Dogs of War." His mission is to get back a vital and deadly formula for a colorless, odorless, tasteless gas than can kill millions.
Note: This tale includes the earliest instance of waterboarding I have ever read.