Copyright 1941 by Comic Magazines, Inc.
The on-sale date is the publication date reported in the U. S. Copyright Office filing.
Van Dern is the name of Batman's maternal family and the pearls are a symbol linked to his mother's death in more modern revelations.
Story riffs on Universal's Frankenstein movies, with Dr. Scratch in search of a brain, aided by his assistant Gargoyle (think Igor), with his intended target being Dr. Nienstine (rhymes with Frankenstein).
Writer revision from John Devlin to ? by Craig Delich 2013-4-7. The Who's Who does not indicate a writing credit for Devlin on this strip.
Dick Mace text story.
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, but that is questionable as I have seen said art and it is definitely NOT Gustavson.
Letterer credit courtesy of Terry Gustafson, Paul Gustavson's son.
Art credits revised from Gustafson to Eisner-Fine by Craig Delich (per note below):
"Upon examination of the original artwork to “Police Comics #4, page 62”, featuring The Human Bomb in the story: “The U-Boat Battle,” it indicates that this specific page, and likely the entire story, was illustrated by the combined talents of Will Eisner and Louis K. Fine and NOT by Paul Gustavson as originally credited to, although Paul Gustavson DID in fact write this particular story. Will Eisner's long-time publisher and art agent, Denis Kitchen, confirmed that “panel 1” from “Police Comics #4, page 62” looks incredibly like Will Eisner’s late 1930’S style of work as seen in the Quality Comics’ “Smash Comics” titles: “Espionage: Starring Black X” series, while the remaining panels featuring The Human Bomb in the heat of battle, resemble the style Lou Fine based on the finely delineated linework, the broken-panel layouts, and the overall positioning of The Human Bomb."