This cover artwork is similar to the cover of Detective Comics (DC, 1937 series) #8 (October 1937).
This is almost certainly by Flessel. Compare with the second spot illustration of 'The Evil Oak' story.
Astarita signs in the final panel of pages 6, 7, 10 and 12, with his full name on the first and third and 'Astarita' on the second and fourth.
Same script as New Fun Comics #1-4 (DC) but new art.
Elven is credited on the second, third and fourth stories (each two pages long), and may be the author also. The first story, four pages in length, is by a different artist, possibly Jon L. Blummer (compare with later Hop Harrigan stories), but there is no 'John Elby' credit visible.