This was actually a series of letters written in late 1892 and early 1893, all addressed "Dear Brother" (this would have been either Charles T. or Frank John Dearborn, both of whom lived in the Boston area), that Herado wrote from the Colorado-New Mexico border area. He signed each one "Your Loving Brother Herado." These were published in the Quincy (Mass.) Patriot-Ledger, probably sometime in the 1960s. I have tried to find the exact issue of the paper without success, but I have a photocopy of the article that I would be happy to share. The article is called "Western Mystery Revealed in Old Letters."