In 1934 "Stars Fell on Alabama", written by Carl Carmer was published by Farrar and Rinehart.
It was a big success, selling three printings, with major reviews being featured in the New York Times,and the new York Herald Tribune.
This book is the source of our modern Railroad Bill legend and the role of Leonard McGowin in it.
A short summary of the 4 pages is that Morris Slater killed a police officer in 1893, escaped via train; and then as Railroad Bill begain breaking into boxcars. On July 3, 1895, he killed sheriff E.S. McMillan near Bluff Springs, Alabama. He was shot in March 1896 at Tidmore's store by R.C. John and Leonard McGowin. John and MCGowin shared the $1250 reward (equivalent to about $31,000 now). McGowin also got a lifetime pass on the L&N railroad. Railroad Bill's ability to take animal shapes was also briefly discussed.
My copy of "Stars Fell on Alabama" contains an introduction by Howell Raines
states that among Carmer's informants : "Earl McGowin, scion of a wealthy lumber family and later director of the Alabama State Docks exposed Carmer to the wiregrass country and to the life and manners of wealthy white Alabama."
Earl McGowin's parents and his grandparents (James Greeley & Ellie McGowin and Alexander McGowin) were Universalists. J. Leonard and James Greely were only two years apart in age - and from the same general area - however I'm unable to tell their connection, it does not seem like they were brothers - and unable to determine if cousins.