Carroll John Daly 
The Tag Murders [EPUB ebook] 
Race Williams #20 (Black Mask)

Race Williams thought he had seen it all until he came face to face with the mystery of The Tag Murderer: the killer who left metal emblems pinned to each of his victims’ corpses. Solving the case is only made more complicated when The Flame, Race’s femme fatale, becomes entangled in the mystery: what’s her role? And is Race in her crosshairs too? One of the best adventures in the Race Williams series. Story #20 in the Race Williams series.
Carroll John Daly (1889–1958) was the creator of the first hard-boiled private eye story, predating Dashiell Hammett’s first Continental Op story by several months. Daly’s classic character, Race Williams, was one of the most popular fiction characters of the pulps, and the direct inspiration for Mickey Spillane’s Mike Hammer.