Black Sheep Sunday - BENJAMIN BUTTERFIELD AKA DAN BRASHER

I'm not sure if this is a Black Sheep post or Unsolved Mystery Case!
Benjamin Butterfield was b. 16 Aug 1886 in Cherokee Co., Ia. and d. 18 Jan 1969 in Fallon, Churchill, Nv.
He was the first born of Walter Scott Butterfield and Lutisha (found spelled several ways) Johnson-Butterfield.
On 12 Sep 1918 he filled out his WW1 Draft Registration Card while he was a prisoner at the U. S. Disciplinary Barracks at Fort Leavenworth, Ks. under the name Dan Brasher. As a child I was told that he had changed his name because he had deserted the Army during the WWI. While trying to locate military records for Benjamin you can imagine my surprise when I found him listed as Dan Brasher! Obviously, he had started using his alias prior to joining the Army.
He was enumerated in the 1920 census as Dan Brasher in 1930 as Ben Butterfield in 1936 he got his Social Security number under the name Dan Brasher and in 1969 when he passed away in Fallon, Nv. he was buried under his alias, Dan Brasher.
The burning question is: Why; What & Where did he do something so horrific that he would change his name; join the Army and live the rest of his life under his assumed name???
There is obviously much more to this mystery and I will write more in depth about why he was incarcerated at Fort Leavenworth in another post :-)