The books were published by New York's Hanro Corporation in late 1951 and early 1952 under the Phantom Books imprint:
Love Me and Die! Phantom 504 (1951)
Crime On My Hands Phantom 506 (1951)
Hunt the Killer Phantom 507 (1951)
Naked Fury Phantom 509 (1952)
Wake up to Murder Phantom 513 (1952)
The Harlequins are all copyright Harlequin and don't mention Hanro but, given the dates on the Hanro editions, the Harlequin editions are clearly not originals. Perhaps Hanro and Harlequin acquired the rights to publish in the US and Canada respectively at the same time but Harlequin just took longer. Harlequin then wasn't technically acquiring "reprint" rights.
Day Keene is a pseudonym for Gunard Hjerstedt (1903 - 1969). Keene became an actor in repertory theater in the early 1920’s. When his actor friends decided to try film, he instead turned to writing, and during the 1930’s was a principal writer for the “Little Orphan Annie” radio show, as well as contributing to the pulps. After he moved to the west coast of Florida, he began writing paperback originals in the late 1940’s, mostly fast-paced crime stories. By the 1960’s, he had abandoned mysteries for mainstream novels.
Carl Hodges (1902 - 1966) was a contemporary of Keene.
Harlequin 167 - May 1952
Harlequin 167 back
Harlequin 168 - May 1952
Harlequin 168 back
Harlequin 182 - August 1952
Harlequin 182 back
Harlequin 185 - August 1952
Harlequin 185 back