Copyright 1941 by Comic Magazines, Inc.
The on-sale date is the publication date reported in the U. S. Copyright Office filing.
Writer revision from John Devlin to ? by Craig Delich 2013-4-7. According to the Who's Who, Devlin did not write this strip.
Manhunter's calling card, left at the end of the story, is in the shape of a shoe print (the same as his chest emblem).
Even though the Who's Who doesn't list Gustavson as a writer of the strip, Mike Kooiman and Jim Amash state in the Quality Companion that he created the strip and wrote it, so the question mark with the script credit has been removed by Craig Delich 2013-1-18. Also verified by Gustavson's son, Terry Gustafson.
Letterer credit courtesy of Terry Gustafson, Paul Gustavson's son.