Letters from Matthew-Louis M. Levin, Jeffrey Lowndes, John Garcia, John K. Austin on the inside front cover.
This story sequence is part of a loose trilogy of Rio stories.
[Part One] The Hide Butchers from Eclipse Monthly #1 & 2.
[Part Two] Satan's Doorstep from Eclipse Monthly #5.
[Part Three] Robber's Roost from Eclipse Monthly #9 & 10.