[citation needed] He allegedly ran away from home at age 15, worked as a cowboy, and was an outlaw by the time he was 20, having killed in Colorado and Wyoming, as well as having robbed trains.

[2] In a 1996 American Cowboy article titled "The Debonair Killer", David P. Grady noted: "Marion Hedgepeth looked like a dude, but 'dangerous' and 'deadly' fit him better".

[3] An article published in the Express Gazette, Volume 20 by "a man from Missouri", who described himself as "a disinterested student of train robbing", indicated that appearances were strategically important to Marion and his crew.

In preparation for the Glendale robbery, he noted, Hedgepeth, "his three pals" and his wife "assembled in that city and rented a house in a fashionable quarter of the town.

Before being sent to the state prison, Hedgepeth informed on a former cell-mate, whom he knew as "H.M. Howard" but was really Herman Webster Mudgett, better known as H. H. Holmes, which eventually resulted in the notorious killer's unmasking, conviction and execution in 1896.